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Metra GMOS-04 Wiring Interface

Connect a new car stereo and retain OnStar®, the audible safety warnings and chimes, and the Bose® audio system in select GM vehicles

216 Reviews | 5 questions - 7 answers

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Item #: 120GMOS04

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Overview

Our take on the Metra GMOS-04 Wiring Interface

Metra's GMOS-04 GM radio replacement interface lets you replace the factory radio in select OnStar-equipped 2000-up GM vehicles using the existing wiring and connectors. Even if you don't subscribe to OnStar, you'll need this adapter to connect an aftermarket stereo.

Metra's GMOS-04 GM radio replacement interface lets you replace the factory radio in select OnStar-equipped 2000-up GM vehicles using the existing wiring and connectors. Even if you don't subscribe to OnStar, you'll need this adapter to connect an aftermarket stereo.

Once you connect your in-dash receiver to the interface, you'll get the great sound you want, and keep these important features intact. The Bose amplified speakers and the OnStar system will operate with your new radio, as well as the door chime and audible safety warnings. This interface gives you convenient plug-in connections for the Axxess steering wheel control adapter (not included) that works with most aftermarket stereos – that means less wiring work for you.

Also, once you turn off the ignition in these GM vehicles, the factory radio continues to play until you open the door. This interface maintains that function with your new aftermarket radio. This interface is compatible with select 2000-and up GMC, Chevrolet, Oldsmobile, Cadillac, Pontiac, Isuzu, and Hummer vehicles. Warranty: 1 year.

Important Note: If you haven't done so already, please enter your vehicle information or call an Advisor at 1-888-955-6000 to find out if your GM vehicle's warning chimes are integrated with the factory radio. If so, certain warning chimes in your vehicle may be disabled by installation of an aftermarket receiver. You must use the recommended Crutchfield interface to retain the warning chimes. Failure to do so may result in serious injury or death.

Note: Most vehicles will require additional installation parts — please identify your vehicle if you haven’t done so. You can also call an Advisor for more information.

What's in the Box:

  • GMOS-04 interface module
  • 16-pin harness with stripped leads
  • 18-pin harness to 12-/24-pin GM harness with stripped leads
  • Installation Instructions
Reviews

Metra GMOS-04 Wiring Interface Reviews

Average Customer Review:

216 Reviews

Just what I needed and an easy installation

Written by: Krist from Northern IL on April 10, 2016

2005 Buick LaCrosse

I ended up getting an incompatible GMRC-01 when I ordered everything because I didn't want to keep on-star. I thought i had done all my homework and was fairly sure my car wasn't factory amplified. Well, once installation day came, i was surprised to find it that it is factory amplified. With the GMRC-01 harness, I got this constant loud white noise hiss from all speakers even at zero volume. Thankfully, it states that you will need the GMOS-04 in the installation booklet somewhere if you have a factory amplified vehicle. Being a Saturday afternoon, I had to pick this interface up at a local big box store. I was instantly surprised by the amount of extra wires and that it already has the wiring incorporated for the steering wheel control adapter. Installation of this was a breeze and it seems to be working just fine. I only had to adjust the on-star volume on the unit I got, the other volumes were spot on.

Pros: Works well right out of the box, easy install, easy to adjust the volume levels for chimes/on-star/factory amp

Cons: GM made it necessary to use these aftermarket solutions to simply install a radio

Does its job, but hard to fit in the dash.

Written by: Phil from Omak, WA on March 24, 2016

2006 Cadillac Escalade
Crutchfield Customer Review (What's this?)

Matches up perfectly, as I would expect from a wiring interface. There are several connections I didn't use as my new head unit doesn't have Nav capability, but it's good to know they are there if a needed them. However, the combination of so many long wires and the box they all plug into made this a challenge to tuck in behind the stereo. Now that I know everything is connected right and working, I will be pulling this back out, cutting the wires shorter, tying of the ones I'm not using, and putting it back in more cleanly. Retains On-Star capability, but since my new head doesn't have a Mute wire, it powers completely off when I activate On-Star. Not a huge deal though, since I don't really use that service and it is nice to know it will still work if I need it.

Pros: Matches factory plugs perfectly. Retains On-Star and factory GPS (if new head unit has Nav capability).

Cons: Hard to fit in the dash. So many extra wires can be daunting for inexperienced installers.

Resolved the whine problem in my truck.

Written by: Paul from Tallahassee, FL on February 16, 2016

Crutchfield Customer Review (What's this?)

For years, I lived with a terrible and annoying whine in my truck. I tried all kinds of filters and radios. Once I installed this device, the problem went away. Hallelujah!

Pros: Resolved whine issues, easy to install.

Cons: None

just what I needed

Written by: Susan S. from denver, CO on February 15, 2016

2007 Hummer H3
Crutchfield Customer Review (What's this?)

Great price from Crutchfield when ordering with my new radio. Excellent customer service and tech support - helped me confirm that this was the right wiring harness for my vehicle and then spoke with Joe in tech support to review my wiring connections to make sure I wasn't missing anything. This harness looked intimidating - seemed like it had a lot of extra wires - but Joe walked me through each one and I had everything connected to the new unit in about 1/2 hour. Not too difficult even for my first time.

Pros: Wires are labeled and color coded, directions are pretty clear, tech support from Crutchfield is awesome

Cons: Looks intimidating for a novice

Noise

Written by: Matt from Birmingham, Al on January 19, 2016

2005 Hummer H2
Crutchfield Customer Review (What's this?)

As others have stated, I experienced distortion and alternator hum. Very frustrated.

Pros:

Cons:

Crutchfield response on January 20, 2016 Once we saw this review, our Tech Support team reached out to help the customer. We'll either help him get the interface working the way it should, or help him return it for an exchange or refund.

Does what it's supposed to do.

Written by: kerk from Minnesota on October 26, 2015

2003 Chevrolet Suburban
Crutchfield Customer Review (What's this?)

We don't ever really use OnStar, but it also manages other beeps toots whistles and dings, so I guess I needed it.

Pros:

Cons:

Fairly Easy

Written by: Aaron L from Tennessee on September 27, 2015

2003 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

Fairly easy to wire up and install. Also got the steering wheel adapter. The instructions for the two were a little muddy because the came separately, but some parts were duplicates. Would be much better if these could be purchased together as a kit instead of buying separate pieces. Took about an hour and a half to prewire everything to get ready to install. Followed install directions, and the unit worked seamlessly with my new radio. Only had to adjust volume slightly to get it where I wanted it.

Pros: Fairly straightforward to install

Cons: Wish it was bundled with steering wheel adapter in same box

GMOS-04

Written by: Linda from Washington on September 22, 2015

Crutchfield Customer Review (What's this?)

After 2 days of scratching our heads on why this was not working correctly, we discovered that the 18 pin connector was not seating correctly into the box (this caused the stereo to turn off and on intermittently). We had to remove and unplug the stereo again and reseat the wires in the box. Problem solved. Wasted a lot of time and mind matter over this one. Have to say Crutchfield has awesome customer service. Tech support was great.

Pros: Now that it is working it seems to be good (have only got 3 days under our belt).

Cons: Because the harness was not quality checked it cost us a bunch of time and hassle to figure out what was wrong.

GMOS-04

Written by: CA Tunes from California on September 13, 2015

2003 GMC Yukon XL
Crutchfield Customer Review (What's this?)

does as described, easy install

Pros: retains factory functions

Cons: none

Don't waste your time

Written by: JohnO from Texas on September 11, 2015

2003 Cadillac Escalade
Crutchfield Customer Review (What's this?)

My initial thoughts when I opened the package was the product was cheaply made and the plastic pieces were ill-fitting. After spending an hour soldering every wire to the aftermarket radio, I installed the radio in my vehicle. The radio powered up and I began to test the functions of the radio to make sure everything worked. There was no audio no matter what I tried. I double checked all the connections and everything was correct. I called Crutchfield and spoke with a technical advisor. He instructed me to try several different things, still with no avail. He advised he would send out a replacement and I should receive it in the next several days. I asked if there was another product available. He advised we could try the PAC5. When I received the PAC5, I was impressed with the packaging and the strict tolerances of the plastic housing. I was more impressed that all the settings are done at the factory (all I had to do was adjust 2 screws to set chime volume and set the mode for my Kenwood Radio-extremely simple to do). The GMOS-04 had numerous settings that needed to be made and still didn't work. Save yourself time and headaches...avoid the GMOS-04 at all costs. The PAC5 is a much better product and as close to plug and play as anything out there.

Pros:

Cons: Cheap Plastic Housing Too many settings that need to be done manually

Product worked as expected

Written by: TL from Pittsburgh, PA on August 27, 2015

Crutchfield Customer Review (What's this?)

This product worked well and as expected.

Pros:

Cons:

Made For An Easy Install

Written by: js from New York on July 24, 2015

2006 GMC Envoy
Crutchfield Customer Review (What's this?)

Retained all the oem features...Accessory Power,On-star,Chimes,Bose and factory amp,Had no problems with instructions and they were straight forward and very clear for my application

Pros: Retained all factory functions i needed,Made for a very easy install.

Cons: Little wire matching involved hooking radio harness to interface harness but not a big deal took 10 minutes and was well worth the time.

Had to call tech support

Written by: cielosf from New Jersey on July 16, 2015

2005 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

First off I wish I had cut off at least four inches of wiring on the wires that get attached to the radio harness. When it was complete it was long and had to be wrapped and tied. I soldered the wires together and used heat shrink tubing so it came out neat and compact. If I had used crimp connectors especially the bell type there would not have been enough room to stuff all this back into the dash of a 2005 Corvette along with the GMOS-04 and relay. Had extra wires left over so I called tech support and went over everything with them to be sure all was correct . The pro's at Crutchfield were a big help. Don't hesitate if you have any doubt's as to what you are doing.

Pros: Harness works like a charm.

Cons: Certainly not plug and play.

Onstar or not Onstar?

Written by: kkrueger from Plum City, WI on July 13, 2015

2004 Pontiac Grand Am
Crutchfield Customer Review (What's this?)

Adaptor plugged right in. I was on my own with the other end of the wires... the directions were more like "general guidance". Would have preferred more specific instructions. My car (2004 Grand Am) didn't have Onstar, so I am not sure why I got a kit for "maintaining Onstar".

Pros: Plugged in on the one end...

Cons: Did I really need it for my car because I never had Onstar?

disappointed

Written by: Anthony from Dover, MN on July 6, 2015

2005 Chevrolet Impala
Crutchfield Customer Review (What's this?)

It works but is cheap had to glue it to keep together. Very cheaply made would go with pac next time

Pros: It works

Cons: It's cheap had to glue pins to gmos so all speakers stay working otherwise works but would have only paid half the price if I'd known it was that cheaply made unsatisfactory for sure

Aftermarket in 02 impala

Written by: CT from Indiana on June 17, 2015

Crutchfield Customer Review (What's this?)

Allowed me to install aftermarket stereo and keep doorchimes and other features

Pros: Allows aftermarket install without keeping factory stereo in loop (other alternative would be to keep linked to system to reset warning lights but store in trunk)

Cons: Somewhat time consuming making connections, also seems I should be able to tune stereo louder than the dial allowed

Works great but confusing

Written by: redflagharley from San Antonio on May 31, 2015

2003 Chevrolet Suburban
Crutchfield Customer Review (What's this?)

This wire kit worked great but had my head shaking for a couple of hours! I had to remove and call tech support the next day to prevent from loosing it. Turns out it was simple just not the best instructions. The kit is for GM vehicles with the Bose and onstar features. My vehicle has the Bose but not onstar. This means there are several plugs and wires on the harness that just float around not connected and not used. Drives me crazy to have all those unused connections but it works!

Pros: Value, function, and options

Cons: Instructions are horrible

Important installation component

Written by: OllieS from Longview, TX on May 20, 2015

2002 Pontiac Grand Am
Crutchfield Customer Review (What's this?)

This made the installation of the JVC KW-R710 head unit I got here happen easily. Only one hiccup in the wiring and that was easily fixed. The alert chime is much quieter then the original which I really like.

Pros: Very easy to hook up

Cons: Two wire colors are very easy to confuse.

Wiring interface

Written by: LesS from Michigan on May 4, 2015

Crutchfield Customer Review (What's this?)

Good wiring interface and the tech support is super.

Pros: Great tech support for any problems.

Cons: None

Metra GMOS-04 Wiring Interface

Written by: Anonymous from Granite City, IL on April 12, 2015

2004 Pontiac Grand Prix
Crutchfield Customer Review (What's this?)

Easy to install. Was very pleased

Pros:

Cons:

Thanks Crutchfield

Written by: JR from Iowa on March 26, 2015

2004 Pontiac Grand Prix
Crutchfield Customer Review (What's this?)

Thanks for including this with the radio. Installation was easy!

Pros: Installation was easy.

Cons: .

Metra VT-GMOS-04 Wiring Interface

Written by: Jerry K from Minnesota on March 19, 2015

2003 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

This product was extremely easy to install and use with a slight amount of technical know-how. The instructions that I got were a bit unclear (I may not have read them all) in how to splice this harness into the aftermarket radio. I ended up cutting the wires and splicing the radio harness into this. Once all was said and done, it worked really well!

Pros:

Cons:

Metra VT-GMOS-04 Wiring Interface

Written by: TKS from North Carolina on March 11, 2015

2003 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

The interface was easy to install. It was more than I needed but at least XM radio can be connected it needed in the future. All other features were transferred and work perfectly.

Pros: Everything was easy to connect and worked as advertised.

Cons: Did not need all the functions it was designed to transfer. A less functional, cheaper adapter would do the job.

Harness Installation made Easy

Written by: Jason1 from Agana, Guam on February 28, 2015

2004 Pontiac Grand Prix
Crutchfield Customer Review (What's this?)

Product was easy to work out and connect together. I would recommend carefully reading the directions just to ensure you do not connect the wrong things together. The color coding for all these units helps make it easier but just be careful. Overall very happy with the product and the ease with which to

Pros: Easy install

Cons: None so far

Easy Install

Written by: Troprice from Texas on February 28, 2015

2005 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

Installed this with my New Pioneer Navigation unit. This made for a very easy install as all the wires are color coded or are outlined in the directions. It was simple to integrate the steering wheel adapter i purchased. Everything was a simple plug and play after soldering all the wires to the units wiring harness. Works much better than the PAC Interface that was installed with previous unit, which malfunctioned for no reason after 2 years.

Pros: Simple Installation

Cons: None

Ok item

Written by: bigjohn from ga on February 26, 2015

2003 GMC Yukon XL
Crutchfield Customer Review (What's this?)

It doesn't do my door chimes all the time the right way but keeps my bose system so I'm happy

Pros: Keeps bose

Cons: Finicky with door chimes

Metra wiring device

Written by: Kim R from Chicago Illinois on January 15, 2015

2003 Chevrolet Monte Carlo
Crutchfield Customer Review (What's this?)

Just as advertised

Pros: Chime sounds cheap

Cons: Works perfectly

Metra VT-GMOS-04

Written by: Ben from Harlingen, Tx on January 13, 2015

2005 Chevrolet Tahoe
Crutchfield Customer Review (What's this?)

Installed on my 2005 Tahoe great up grade. Like everything about it. Works well

Pros: Does what it's suppose to do

Cons: None

Worth the extra Cash

Written by: John C from Arkansas on January 10, 2015

2003 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

The Metra VT-GMOS-04 Wiring Interface works as advertised. Just follow the instructions and connect the wires by color and your set. The chime and audio volume can can be adjusted to your liking. I installed it on a 2003 Chevy Silverado.

Pros:

Cons:

Best option on the market

Written by: John T from Hampton, VA on December 29, 2014

Crutchfield Customer Review (What's this?)

Best option on the market that I could find

Pros: Ease of install

Cons: none

Metra VT-GMOS-04 Wiring Interface

Written by: Anonymous from Tennessee on December 28, 2014

Crutchfield Customer Review (What's this?)

The Metra VT-GMOS-04 Wiring Interface is a great addition to add when installing a new radio.

Pros: -Clear sound and just works

Cons: -Way to many wires. -must be soldered together.

Metra GMOS-04 Wiring Interface

Written by: Anonymous from NY on December 28, 2014

2005 Chevrolet Impala
Crutchfield Customer Review (What's this?)

It works ok, I don,t use On Star so I can't comment on that part.

Pros: Ok

Cons: To many wires to hook up, directions could have been better.

Works great

Written by: Rj from Sunshine state on November 28, 2014

2004 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

I ordered the wiring interface and steering wheel adapter together. I'm glad I did they work perfectly. Everything works great.

Pros: Easy to install

Cons: None

Excellent

Written by: Brotherwind from T or C NM on November 13, 2014

2002 GMC Envoy
Crutchfield Customer Review (What's this?)

Crutchfield team was excellent. After getting wrong part from other dealer these guys cleaned that guys mess up. Works perfectly. Took but minutes to install. No problems. Rain sensors still working fine , don't use onstar but it seems like it's properly powered up. Doesn't allow all 6 speakers to function , but that's Bose's stuff. Will definitely go with these guys. Prices as good as anywhere else. Fast delivery. Even emailed me our online chat conversation which is nice so everything is open. Thanks Crutchfield...

Pros: Quick and easy install. Everything works. Quick delivery. Excellent team work.

Cons: The Bose system will not allow this harness to utilize all 6 speakers. Not their fault , it's a Bose thing I'm told by installer.

Metra GMOS-04 Wiring Interface

Written by: Anonymous from Rockland, MA 02370 on November 11, 2014

2007 Chevrolet TrailBlazer
Crutchfield Customer Review (What's this?)

Really made installation easy.

Pros:

Cons:

Didnt work

Written by: Charlie from Mt on November 5, 2014

2004 Pontiac Grand Am
Crutchfield Customer Review (What's this?)

Just spent almost $300 on new stereo and this item to make it work. Confusing to install and ended up mutilating it, so unreturnable. So now have a torn up car and down almost $300.

Pros:

Cons:

Metra GMOS-04 Wiring Interface

Written by: Bdubtex from Memphis, TN on October 2, 2014

Crutchfield Customer Review (What's this?)

Works great

Pros:

Cons:

2007 Chevy Silverado 1500 with Bose

Written by: Anonymous from Illinois on September 26, 2014

Crutchfield Customer Review (What's this?)

Used on an 07 Silverado with bose speakers and a JVC KW-R910BT head unit. Works great!! Customer Service was beyond excellent as I failed to order this with the HU but no problem. Recieved in 3 days and even got the special price, 1/2 off, that I would have recieved if I would have ordered both together, instead of being charged full price. :-)

Pros: Everything!

Cons: None

Perfect interface for my Suburban

Written by: Paul from Houston, TX on September 24, 2014

2004 Chevrolet Suburban
Crutchfield Customer Review (What's this?)

It works and easy to install.

Pros:

Cons:

Metra VT-GMOS-04

Written by: Jorge from Haines City, Florida on September 19, 2014

2006 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Plug and play, no issues

Pros:

Cons: Too bulky

Good Product

Written by: DCP from Houston, TX on September 2, 2014

Crutchfield Customer Review (What's this?)

This product is a bit intimidating to look at, but the instructions are reasonably clear and it works as advertised for what I am doing with it. I am using it only to connect to a Bose amp. I cannot comment on the other functions.

Pros: Facilitates an aftermarket head unit to a Bose amp. Sets itself up. Unlike competitive product, it allows the fader to work.

Cons: Bulky with a lot of wire to move out of the way during installation.

Metra VT-GMOS-04 Wiring Interface

Written by: KellyK from Georgetown, Tx on August 28, 2014

2006 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

Wiring harness works great. The wiring instructions were easy to understand. My only complaint is that there needs to be some additional info on using the ASWC interface.

Pros: Clear and concise wiring instructions.

Cons: Needs additional elaboration about using the ASWC interface with it.

Metra GMOS-04 Wiring Interface

Written by: Anonymous from Roanoke Va on August 6, 2014

Crutchfield Customer Review (What's this?)

Was not a good unit

Pros:

Cons:

5 stars!

Written by: Wyatt from Edgerton, MN on August 2, 2014

2004 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

Great purchase, easy install and lives up to its perks!

Pros: Easy install

Cons:

Wiring harness

Written by: MikeH from Tulia, TX on July 26, 2014

Crutchfield Customer Review (What's this?)

Works very good in 2004 Silverado 1500

Pros: Easy to install

Cons: Too many red wires and no explanation which one goes to what.

GMOS-04 adapter cable

Written by: zbee062 from Anderson, SC on July 22, 2014

Crutchfield Customer Review (What's this?)

I recently purchased a DNX890HD to replace an older unit in a 2008 non-Bose Corvette. The instructions were reasonably clear and I successfully spliced the adapter and the 890 unit together and everything worked first time. This included rear and forward facing cameras, OnStar (no subscription but music correctly muted automatically while listening to the recorded message). The nav screen automatically switched to the rear facing view when reverse was selected. The HD radio worked very well, as did an iPod, an MP3 player (via the Kenwood KCA-IP202 cable) and an iPhone 4S via the 890 built in Bluetooth system. The speakers could be controlled as per input to the 890 unit. Chimes worked correctly when the door was opened in accessory mode. Did not test other possible alerts. Had to read instructions closely several times to catch that the GMOS-04 cable red wire connects to the red wireS (i.e. both?) from the 890 unit. Including the word "both" red wires would have saved some time trying to understand which red wire to use. Per comments below one red wire should be connected to the steering wheel controls which was not used on this installation.

Pros: Instructions were good and easy to follow. I found it useful to read other reviews in various forums before splicing the cable to gain a better understanding of any potential problems that may arise (there were none for me).

Cons: None except it looks a mess when everything is connected, but that is hidden from view when installed. Only tested for one day in the car as the Nav system failed ("no maps available") , nothing to do with the cable but it prevented longer term testing as the 890 unit was returned.

Metra GMOS-04 Wiring Interface

Written by: Anonymous from Lexington, Kentucky on July 14, 2014

2004 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

Very complicated with poor instructions

Pros:

Cons:

Nice unit

Written by: Anonymous from Lincoln Ne on July 1, 2014

2005 Chevrolet Avalanche
Crutchfield Customer Review (What's this?)

Straight forward wiring

Pros:

Cons:

Does what it's supposed to do...

Written by: S from Kansas City on June 3, 2014

2002 GMC Envoy
Crutchfield Customer Review (What's this?)

Works perfectly in my 2002 GMC Envoy.

Pros:

Cons:

Works with a little intervention.

Written by: Allen E. from Oswego, IL on April 28, 2014

2002 Chevrolet Monte Carlo
Crutchfield Customer Review (What's this?)

Not a difficult install if you can handle a soldering iron and read. Unfortunately the directions were not 100% accurate. Probably i the nature of a "universal" adaptor. Had to experiment a little with the wires that were supposedly "not used". Head unit didn't receive power at first after follwoing teheir instructions. Turned out that the three wires that were to be "cut" and not used, 2 had to be reconnected for the head unit to function. So far works fine . . . with a little ingenuity on my part.

Pros: Works.

Cons: Not perfect instructions

Metra GMOS-04 Wiring Interface

Written by: Anonymous from sonora, Tx on April 21, 2014

Crutchfield Customer Review (What's this?)

It works good, it does what it supposed to. The only concern I had was during installation there were two bat. Red wires, now were both of those wires supposed to be connected together or was just one supposed to be connected. I connected both of them together to the12v source wire. Should I leave both of them connected or go back in there and just leave one connected?

Pros:

Cons:

Crutchfield response on April 23, 2014 One of those red wires is meant for powering the optional ASWC-1 adapter for the steering wheel controls. Our tech support team followed up with the customer to let him know.

Easy install... Easy life

Written by: MisterBond1989 from Adelanto on April 10, 2014

2003 Pontiac Grand Am
Crutchfield Customer Review (What's this?)

This adaptor is awesome! Makes things easy to install another radio. No cutting or splicing of wires. Only one issue that I have found while using this product is that the factory Monsoon amp in the 1999-2005 Pontiac Grand Am does not get bypassed. If you have a Monsoon equipped Grand Am; the factory external amp needs to be used in order for the factory speakers to work. This makes sound quality very poor and low. If this is the case for you, I suggest installing an external amp and get rid of the Monsoon amp. Beside that issue; great product!

Pros: Makes install of radio easy, clean, and worry free. No cutting of the factory wires needed.

Cons: Does not bypass Monsoon amp in the 1999-2005 Pontiac Grand Am.

Does it's job

Written by: JYaz from Hanover, PA on April 10, 2014

2005 GMC Sierra 2500/3500
Crutchfield Customer Review (What's this?)

It does what it should

Pros: It works

Cons: All of the wires are confusing. Instructions aren't the best.

05 gmc truck upgrade

Written by: Doug H from Charleston S.C. on March 25, 2014

Crutchfield Customer Review (What's this?)

Upgrading the truck with a sony cd player,truck has the bose radio speaker system,and the connections were spot on,cant imagine how much better the truck sounds now,that i have a real radio in it

Pros: easy to install,ajustable door chime module

Cons: blue/white wire for amp signal looks alot like the blue/pink wire,that should be pinker,or not even blue at all

Great adapter

Written by: David from Fremont, NC on March 9, 2014

Crutchfield Customer Review (What's this?)

Easy install and worked great with my 2005 Avalanche with Onstar,Bose Sound System and Navigation. You may want to shorten the wires on the 16 pin connector unless you have plenty of room for the wires and your new stero.

Pros: installs quickly and instructions are very clear and easy to follow. Crutchfield support was extremely helpful but you shouldn't need them with this adapter. I had issues with another adapter not working with my vehicle and required their help.

Cons: None

Simple

Written by: Dahveed18 from Flint, MI on March 9, 2014

2005 Pontiac Grand Prix
Crutchfield Customer Review (What's this?)

Simple to use!

Pros: Adjustable gain, adjustable OnStar volume, adjustable chime level

Cons: None

Metra VT-GMOS-04

Written by: Sean P from Southern California on February 22, 2014

2005 Chevrolet Avalanche
Crutchfield Customer Review (What's this?)

Plug and Play, worked well

Pros: easy install

Cons: needs second cable for steering wheel

Worked well

Written by: CCVirginia from Fairfax, VA on February 18, 2014

Crutchfield Customer Review (What's this?)

Worked well to integrate with a 2005 Suburban. Retained all the factory functions.

Pros:

Cons:

Works

Written by: aditaa from Austin, TX on February 8, 2014

2005 Chevrolet Silverado 2500/3500
Crutchfield Customer Review (What's this?)

Works as expected

Pros: factory amp works onstar and door chimes still work via radio speakers

Cons: very messy wiring configuration still need extra part for steering wheel controls

Worked perfect

Written by: Lox4rox from Texas on February 2, 2014

2004 GMC Yukon XL Denali
Crutchfield Customer Review (What's this?)

Worked perfect with my 2004 Denali. Plug and play once the harnesses are wired up...instructions were excellent. All onstage and chimes at just as with factory head unit.

Pros: Easy if install. Everything works per factory norms.

Cons: None

Does what it says it'll do

Written by: JT from Bosque Farms, NM on January 25, 2014

2003 Chevrolet Silverado 2500/3500
Crutchfield Customer Review (What's this?)

Easy to install, works as advertised. Like the fact that I can turn the door chime way down.

Pros: Ease of installation, good instructions

Cons: None so far

Works well

Written by: Jeff M from San Antonio, TX on January 3, 2014

2003 Chevrolet Suburban
Crutchfield Customer Review (What's this?)

This unit was necessary to retain the door chimes and the Bose system in my truck. My truck isn't equipped with OnStar, but this unit will accommodate those vehicles that do. I would prefer not to have the extra wires floating around the dash, but for the price, I'll live with that. I had a couple of questions on the install, but as always, Crutchfield customer service was able to answer them quickly and the install was a breeze.

Pros:

Cons:

Unit works, instructions horrible

Written by: Steve KY from Ashland KY on January 3, 2014

Crutchfield Customer Review (What's this?)

First of all, the thing does what is supposed to. The instructions are miserable. Hook up red wire,it has two. several others are the same way. I called Crutchfield and they told me how to make it work. Without that it would ne impossible.

Pros: Works

Cons: Have to call to get help, not so good when trying to install Christmas present on Christmas day.

Works well

Written by: Matt from Milwaukee, WI on January 3, 2014

2006 GMC Sierra 1500
Crutchfield Customer Review (What's this?)

Works as its intended, Instructions could be a bit clearer though.

Pros: Adjustable chime volume

Cons: n/a

Metra GMOS-04 Wiring Interface

Written by: Anonymous from Lansing, Mi on December 22, 2013

2003 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

Very easy and clear instructions, everything worked and made sense. Potentiometer was a great but unadvertised bonus.

Pros:

Cons:

Perfect for GM with Bose

Written by: EA from El Segundo CA on December 19, 2013

Crutchfield Customer Review (What's this?)

Works perfectly. Easy to install

Pros: Works perfectly. Easy to install

Cons: None

Hope the new version is better than the old

Written by: Ross from Chesapeake, VA on December 13, 2013

Crutchfield Customer Review (What's this?)

I had the exact same adapter previously installed in my 2003 silverado SS. After about 4 years my battery died out of no where - after months of trying to diagnose the issue and finally taking it to a stereo shop they found this adapter to be the cause of a 754ma draw. I recently purchased this one and it solved the issue. After reading online this it apparently a common issue but since no other adapter is out there you're pretty much out of luck if you want to keep BOSE and chimes with an aftermarket HU. That aside - the instructions are great - install is painless assuming you know how to strip and crimp wires. The overall bulk added to the harness is extremely annoying but again, what other choice do you have? Fingers Crossed this unit works.

Pros: Easy Installation, Good instructions

Cons: Overpriced, does not last, bulky mess added to your oem harness

Simple and easy to install

Written by: Drock77 from Claremore, Ok on December 3, 2013

Crutchfield Customer Review (What's this?)

Simple to wire up and easy to install

Pros: Simple to wire up and easy to install, it also has a volume knob to increase or decrease the vehicle chime volume.

Cons: N/A

Metra GMOS-04 Wiring Interface

Written by: Anonymous from Aurora IL. on November 30, 2013

2001 Pontiac Grand Am
Crutchfield Customer Review (What's this?)

Works well, only reason I gave a 4 is because we had to call for wiring issue, it is a bit universal which I understand. the good news is the staff is great, always answer the phone and talk you through it.

Pros:

Cons:

great quality product.

Written by: richie o. from bronx ny on November 23, 2013

2006 Chevrolet TrailBlazer
Crutchfield Customer Review (What's this?)

Great Product. harness works like factory with newer modern cars. Love the web site.very helpfull. cant wait to do more business

Pros: Crutchfield knows there stuff

Cons: None

Pure awesomeness

Written by: jasonsfn from Sacramento, CA on November 17, 2013

Crutchfield Customer Review (What's this?)

Being able to install an top of the line Alpine and also have it integrate with all of my factory equipment on my 2004 Tahoe was amazing, this wiring kit is a must! would use it again in any applicable install situation.

Pros: Allows you to keep all of the things you loved about the factory receiver and on star while upgrading your sound. It works and sounds amazing. even has open slot for the steering wheel harness to plug right in saving time and the use of extra wiring.

Cons: Cant really find any.

A Must Have

Written by: Anonymous from Sussex, WI on November 7, 2013

2006 GMC Envoy
Crutchfield Customer Review (What's this?)

This is a must have ... It was very easy to hook up and works great. I would strongly recommend this to anyone hooking up an aftermarket radio.

Pros: Easy to hook up and as always the customer support is the BEST

Cons: Bigger print and a easier to read diagram

It just works.

Written by: Dirk A from Jonesboro, AR on November 6, 2013

2008 Pontiac Grand Prix
Crutchfield Customer Review (What's this?)

Ok....first off I have been hesitant about upgrading the head unit it my last few GM vehicles due to interface issues. With a 2008 Grand Prix that is not going anywhere, and no way to use any external devices decided it was time to upgrade. Our car has the factory amp with the "Monsoon" system, and I was pretty sure that I would have to bypass it. After reading the capabilities of this integration adapter......it seemed I could retain the amp, which would simplify installation. It did this perfectly, along with the retention of the factory chimes. The device itself is just a small black box, with 2 wiring harness. It "inlines" between the head unit and the factory plugs. I did not have to adjust the volume level for either the OnStar, the chimes, or the speakers. This procedure if needed is described in much better detail on the manufactures website. THIS IS IMPORTANT!! If like me, you tested everything before buttoning it back up, the chimes for the "key in ignition", lights on, door open, etc. DID NOT WORK until I plugged the Driver Information Center (DIC) back up. At first I thought it was a problem with my wiring or the Metra unit, but since I couldn't leave the car apart....I went ahead and put it all back together.....everything worked as needed after the DIC was plugged back up. If Metra could have kept the steering wheel controls and kept the date display on the DIC, the unit would have been perfect.

Pros: Simple instal, works as needed, good build quality.

Cons: High MSRP, some features could be added, poor included instruction.

As if it were factory

Written by: Ray S from Sandwich Il on November 3, 2013

2003 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

I fairly strait forward wiring job works great.

Pros: A quick download of a PDF from the web site and it was a breeze

Cons:

Metra VT-GMOS-04 Factory Integration Adapter

Written by: Jack from Castro Valley, CA on October 31, 2013

Crutchfield Customer Review (What's this?)

After installing this unit in my 2005 Grand Am GT soldering every connection and using heat shrink. I had nothing but problems. I double and triple checked the wiring all was correct. I had low volume even after using the adjustment knob. (it did nothing) The sound only worked with the door open and chimes ringing. close the door and no sound but the radio still had power. I called Cructhfield tech. The tech person was very nice and tried to help but even after I tried all the things he suggested nothing changed. So I removed the unit and installed a GMOS-01 similar to the 04 but without the BOSE feature. I don't have BOSE in this car so I really didn't need the 04 version anyway. So now all is well.

Pros: None for me.

Cons: Did not work. I had to cut all those beautiful connections I made.

Crutchfield response on November 3, 2013 We forwarded this review to our Technical Support team for follow-up. Lifetime tech support comes with every Crutchfield purchase.

Metra VT-GMOS-04 Factory Integration Adapter

Written by: Mike F from Fort Worth, TX on October 28, 2013

2003 Buick Rendezvous
Crutchfield Customer Review (What's this?)

Kept my door chimes and OnStar integrated on my 2003 Buick Rendezvous. FYI, READ ALL INSTRUCTIONS!! I didn't read where you are supposed to set the gain on the harness. I thought my newly purchased JVC bluetooth unit was a terrible buy for the 1st few days. Then, I went back and read all the instructions on the Metra integration adapter. Opened the dash back up and set the gain. Made ALL the difference. Speakers are rocking once again!

Pros: Keep integration

Cons: Some of the wiring instructions aren't exactly clear, but managed to get it figured out without too much hassle.

good adapter

Written by: chefjoey from woodridge, il on October 26, 2013

2005 Chevrolet TrailBlazer
Crutchfield Customer Review (What's this?)

needed this to install aftermarket radio in my 2005 trailblazer with onstar, satellite radio, and factory chimes

Pros: works ok

Cons: wiring instructions do not cover all the wires that are on the harness, hard to adjust the volume for the onstar, need to pull the radio !

Great product keeps the bells and whistles in your automobile.

Written by: Pasquale M. from Massachusetts on October 24, 2013

2008 Hummer H3
Crutchfield Customer Review (What's this?)

If you want to keep your car/truck factory with the bells and whistles this item is a must. Easy install.

Pros: Easy install just follow the directions. Others have said that this install created a battery drain. Only way that will happen is if you cross your power line (red) with the memory line (orange). A perfect solution to keeping on star and door chimes on your vehicle. Super easy to install with you after market radio.

Cons: None

Metra GMOS-04 Wiring Interface

Written by: DarrellD from San Antonio, TX on October 11, 2013

Crutchfield Customer Review (What's this?)

This harness worked flawlessly

Pros:

Cons:

Metra GMOS-04 Wiring Interface

Written by: d500 from Independence, KY on October 2, 2013

2004 Chevrolet Avalanche
Crutchfield Customer Review (What's this?)

Its a nightmare to get hooked up but it works very well when you finally figure out the directions

Pros:

Cons:

Worked right out of the box.

Written by: Trevor from Albert Lea, MN on September 16, 2013

Crutchfield Customer Review (What's this?)

There are extra instructions on the Metra website that does not show up with the unit, but everything installed without a hitch. You need to set the door chime first with the adjustment screw and then use the same screw to adjust the volume of the head unit, this is the part that is on the website.

Pros: Worked flawless

Cons: Price, directions not complete.

Metra VT-GMOS-04

Written by: Steve D from California on September 5, 2013

2003 GMC Sierra 2500/3500
Crutchfield Customer Review (What's this?)

This adaptor works perfectly! I used this to install a Kenwood DDx470 in my 2003 GMC 2500HD. The directions were well written and easy to follow. Everything works as it should. I also used the steering wheel controls adaptor. The pre-wired connectors make it simple to install.

Pros: Easy to follow instructions.

Cons: None. Everything worked perfectly.

Metra VT-GMOS-04 for GM Vehicles

Written by: JimM from Greenville, NC on September 3, 2013

2006 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

Used this adapter to connect a Kenwood HD with Nav system into a 2006 Corvette. The connections are very well explained into the instruction and wire color code matched very well with the wire of the Metro adapter. This made it very easy for myself to install. The only issue was the instruction for corvettes(only) indicated the adapter needed to be attached to a relay. The instruction should note that the relay is not on the car and would need to be purchased and installed using a fuse tap. In all it went very well as it worked without having to make any adjustments or corrections.

Pros: Color codes on wire matched codes on the Kenwood radio

Cons: Bulky wire pack to place behind the radio.

Great product

Written by: Anonymous from Lutz florida on August 29, 2013

2004 Cadillac Escalade
Crutchfield Customer Review (What's this?)

Great part thank Crutchfield

Pros: Easy installation

Cons: Non

Metra GMOS-04 Wiring Interface

Written by: Anonymous from Franklin, Tn on August 22, 2013

2003 GMC Envoy
Crutchfield Customer Review (What's this?)

Works great the only thing is in the instructions it says the knob it for chime volume. it's not it controls the amp volume

Pros:

Cons:

Integration Kit

Written by: Awt2b! from Seattle, WA on August 12, 2013

Crutchfield Customer Review (What's this?)

I used this harness for our 08 TrailBlazer SS to replace the Bose with a Kenwood. Everything I needed was included. There is no reason not to buy it from Crutchfield...It was a lot more money at any other place I looked!!

Pros:

Cons: For the Bose/OnStar there is a BabyBlue wire that you need to hook up for the proper sound to work. Then on the 'inline' box that comes with the kit...It has a small blue adjustment knob that we did not see until after we hooked up the blue wire to get sound. Then we turned the blue adjuster clockwise and UP went the volume...make sure your Deck is on about volume 2 when turning up the blue dial.

Worked great but still took work

Written by: Soldier meister from Pasadena, CA on July 26, 2013

2004 Chevrolet Suburban
Crutchfield Customer Review (What's this?)

Worked great! Wires colors matched and everything. I soldiered the connections so it took a little longer. Note, when connecting the steering control adapter you the 12pin connected to this not the 12pin that comes with the steering wheel controls adapter.

Pros: Works great

Cons: Lots of wires - would be awesome if it used quick connects.

Current replacement interface for GM trucks

Written by: Angelo from Virginia Beach, VA on July 23, 2013

My old interface was on its way out, I had an alpine deck in my 2004 Sierra 2500 HD for almost 6 years from Crutchfield, so I called them and they sent this interface for half price to replace it. Shipping and customer service as always is A++ with these guys, but the interface itself is as expected from anything made in China....less than sub par. The wiring was fine, soldered everything into place, the box (interface) itself was a dud, so after running the gambit of troubleshooting, I called up Crutchfield and they sent me a replacement for free with a pre-paid return via UPS. The second one worked fine, I really appreciate all the years of great support guys.

Pros: Easy install with a bit of common sense and the right tools, supports a wide variety of GM vehicles.

Cons: Made in China and is junk....but since it's the only reasonable option to run aftermarket radios in GM trucks.....

Do not buy this product!

Written by: Joe S. from Lowell, MI on July 13, 2013

Do not buy this adapter unless you plan to leave your car connected to a battery charger every night. Within two days of installing this, my battery was completely dead. I fully charged the battery, and it died again within two days. I had the battery tested, and it was fine. This is the second GMOS unit I've installed that has caused this problem, and yes...it was installed correctly. Not that the instructions are particularly well written, but the wire connections are not that complicated. I ended up removing the GMOS unit and just keeping the wiring harness from it to connect to the vehicle's wiring harness...and surprise...the problem is gone. Ultimately I lost my OnStar (which I don't use) and my door chimes (who cares). It sucks that I had to pay this much for a $5 wiring harness, but that's what I get for not reading all of the reviews. It turns out many people have had the same issue with this unit. Crutchfield should realize this unit is junk and stop telling people its "required"...it most certainly is not, and it will cause you nothing but headaches. If I could have given this thing less than 1 star, I would have.

Pros: Easy to connect, maintains door chimes and OnStar. It also allows you to make good use of a battery charger and makes you late for work until you pull it out. The only useful part of it is the harness that connects to your car's factory harness.

Cons: Seriously diminishes the sound to your speakers and drains your battery when the car is off.

Metra GMOS-04 Wiring Interface

Written by: Anonymous from Indianapolis, IN on July 12, 2013

2002 GMC Envoy
Crutchfield Customer Review (What's this?)

Product worked as desired. Resolved issue with another radio that I bought, and no sound would play after it was installed. Returned that radio, bought new radio from here, with this adapter and all is working we. The real issue was the wiring, and I called support twice. Waited just a few minutes each time and they were able to resolve my problem in just a few minutes..

Pros: Crutchfield support was awesome

Cons: None

Easy install.

Written by: Michael from Independence,MO on July 10, 2013

2006 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

Easy install, unless you have Bose. Had to retire Bose amp in center console to bypass it. Not bad. You will have to bypass Metra module with your speaker leads if getting rid of Bose amp. Then run wires for right front speaker coming out of module to input on Bose amp right front. The from output right front on Bose amp to parrot speaker you have to install under cup holder. Works like a charm this way.

Pros: Easy to install. Easy to adjust.

Cons: Need additional speaker to hear warning chimes and OnStar and must bypass factory amp to get the most out of your new stereo.

Metra GMOS-04 Wiring Interface

Written by: Anonymous from Gilberts, IL on July 8, 2013

2005 Pontiac Grand Prix
Crutchfield Customer Review (What's this?)

Perfect, couldn't work better

Pros: Great instructions and labeling

Cons:

GMOS-04

Written by: T from Litchfield, IL on June 24, 2013

Crutchfield Customer Review (What's this?)

What ever you do, try everything before putting your dash back together. Had to bypass hooking my parking brake wire to the lt. green wire of the gmos-04. If these are supposed to be vehicle specific they need to work on them some more. Thanks to the crutchfield techs they are the best. Only had one that wasn't much help but call the guy that helped me the most. Thanks Casey

Pros: easy to hook up

Cons: extra wires again and a pain to try and put them behind the radio in the dash neatly.

GMOS-4

Written by: Nick from Houston, Tx on June 22, 2013

Crutchfield Customer Review (What's this?)

A-

Pros: Retained all factor and Onstar chimes as promised.

Cons: Loss of stock amplifier but system is upgradable due to aftermarket radio.

Works OK

Written by: LBRU from Falls Church, VA on May 27, 2013

Crutchfield Customer Review (What's this?)

Works fine

Pros: Easy installation

Cons: None

simple, sounds good.

Written by: billy from auxvasse mo on May 25, 2013

2004 Chevrolet Avalanche
Crutchfield Customer Review (What's this?)

simple, works great.

Pros: easy to install. works.

Cons: having to buy to begin with.

Perfect replacement for GM09SR interface

Written by: Angelo from Va Beach, VA on May 14, 2013

I had an Alpine 500CDA9856 deck in my 2004 GMC sierra, the old interface blew (it was a Scoshe GM09SR). I called up Crutchfield after almost 5 years of having the radio, and they walked me through the troubleshooting and gave me this new interface at half off. It arrived in 2 business days UPS ground, was relatively easy to install, the instructions were clear and the colors of the wires all match with my radio's harness. With a wire strippers, soldering iron, and tape and a little G2, you'll be able to get this wired up in no time. If all else fails, their tech support is on standby and willing to help, the simple fact that their techs answer the phone even at 9pm and have the answer to my issues even after five years has made me a lifetime customer.

Pros: Easy to install, made in USA.

Cons: N/A

Works Great,, Kepy My Factory Chimes, and Bose System.

Written by: Bruce from Chicago, Il. on May 8, 2013

2004 GMC Yukon
Crutchfield Customer Review (What's this?)

The GMOS-04 works very well, and I was able to keep my chimes, and use my current Bose Speaker System. Follow the directions, and if you have a problem, you can call tech support and they will talk you through it. All the wires are color matched, and simple to put together, If the chimes are too loud for your taste, the volume is adjustable. Forget about the bad reviews, and get this unit if you have chimes and a Bose Speaker System. You can also add a steering wheel control mudule as well if you desire. I decided I did not need it because my Head Unit came with a remote, so I am sastified. Great product, and Crutchfield sells it for half price with a purchased radio. Great Deal!!!

Pros: Works great at factory setting, if connected as directed.

Cons: None.

Adapters are a must for easy install

Written by: Matthew from Minnesota on May 7, 2013

2004 GMC Yukon XL
Crutchfield Customer Review (What's this?)

As much as I try to "save" money, these adapters are absolutely necessary to help retain your sanity - they make the installation of any stereo that much easier... I'm just glad they give us 50 percent off when we purchase it with the system! Read people had problems with some units - no problem with ours.

Pros: Makes installation 5000 times easier and faster!

Cons: Adds a little expense to your project (but worth it!)

great

Written by: LAURAcr125 from palmdale, CA on April 22, 2013

Crutchfield Customer Review (What's this?)

I missed my Pioneer!

Pros:

Cons:

Good product

Written by: Anonymous from Lexington, SC on April 17, 2013

Crutchfield Customer Review (What's this?)

I am not a wiring expert. So the wiring could some how be made simpler like a website that matches all aspects together to tell you which wires to use and which wires you won't be using

Pros: Works good

Cons: Wiring instructions could be made simpler

ok

Written by: Anonymous from DSM on March 25, 2013

2001 Pontiac Grand Am
Crutchfield Customer Review (What's this?)

took two unit to get it to work on my 01 grand am

Pros:

Cons:

low sound/ crappy highs

Written by: alex from germany on March 15, 2013

Crutchfield Customer Review (What's this?)

it works but, i still am having trouble with my front speakers the quality of sound is unacceptable..

Pros: chimes

Cons: crappy sound from front speakers you have to increase the volume and it becomes distorted

Hopefully second one works better than first!

Written by: Anonymous from Buffalo, MO on February 26, 2013

2004 Chevrolet Monte Carlo
Crutchfield Customer Review (What's this?)

I had a factory stereo and Bose system and replaced stereo with a Pioneer AVH3400. After getting everything hooked up, it didnt seem to be near as good as my factory stereo which sounded awesome. The only reason I replaced the stereo was I wanted blutooth and ipod controls. Once installed, I'm getting virtually no sound from front speakers. I jumped around GMOS unit with front speaker wires (per Crutchfield tech support) and they sounded great. Credit Crutchfield for doing a great job helping determine the issue and trying to resolve it. We'll see when the replacment unit gets here. If it doesnt work, I'm just gonna bypass the speaker hookups on this thing.

Pros:

Cons:

JUNK JUNK JUNK

Written by: Joshua from Twin Cities, MN on February 7, 2013

2004 Pontiac Grand Prix
Crutchfield Customer Review (What's this?)

I'm trying to install this GMOS-04 in a 2004 Grand Prix GTP, and the new interface makes my speakers pop when I turn the key from off to acc/on. Or when I open/close the door under certain situations. I've been on the phone with crutchfield at least 15 times to find a work around, and nothing. (Not their fault, this is a crappy product). After looking around online, and reading other forums and threads, I can see that I'm not the only one. It's still not fixed right now.

Pros:

Cons:

Metra GMOS-04 Wiring Interface

Written by: Anonymous from Moultrie, GA on February 5, 2013

2003 Chevrolet Impala
Crutchfield Customer Review (What's this?)

Great

Pros:

Cons:

Metra GMOS-04 Wiring Interface

Written by: Terrance from Church Point, La on January 23, 2013

2006 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

I like that I can still use with my bose speakers and still have OnStar. The installers had a hard time getting the door chimes to work. I sometimes wish that part didnt work because the volume of the chimes is to loud.

Pros: Still able to use OnStar and have bose speakers

Cons: Door chimes is to loud. Compared to before Id say its 10xs louder. Which is not something I want to hear everytime I turn on truck or open door. I really hate that it's so loud!!!! Can you lower the volume??

Crutchfield response on January 23, 2013 We forwarded this review to our Technical Support team for follow-up. Lifetime tech support comes with every Crutchfield purchase.

Metra GMOS-04 Wiring Interface

Written by: josh from pleasant view,tn on January 5, 2013

Crutchfield Customer Review (What's this?)

got as a Christmas gift from parents, they ordered the wrong part, was able to return for correct one with even trade and postage paid return, my dad and i installed it in a few hours

Pros:

Cons:

gmos-04

Written by: keith from groveport ,ohio on December 25, 2012

Great product,excellent tech support department.Thumbs' up for you guys.

Pros:

Cons:

No Steering Wheel Control

Written by: B.L. from Columbus, OH on August 15, 2012

2004 GMC Envoy
Crutchfield Customer Review (What's this?)

Very disappointed that I lost my steering wheel controls. The product info is correct except for that one issue. Installers said I needed an additional component, so I opted not to. Maybe just an installation error, but future purchasers should doulble check.

Pros:

Cons:

Almost perfect

Written by: Greg D. from Kansas City, MO on August 2, 2012

2004 Hummer H2
Crutchfield Customer Review (What's this?)

The instructions are very clear (except as some other reviewers have pointed out there are two red wires not the one mentioned in the instructions.) The only down side about it was my steering wheel controls are not doing anything after I did the install and that is one feature said to be maintained by the use of this device.

Pros: You can maintain your onstar and chimes when moving to an upgraded stereo.

Cons: Didn't maintain the steering wheel controls as advertised.

GM adapter

Written by: stevem from fl on July 27, 2012

Crutchfield Customer Review (What's this?)

Works great, take your time and read directions a couple times before wiring. Put it in an 04 Chevy 3500.

Pros: Keeps all factory chimes. allows volume adjustment for chimes.

Cons: A lot of wiring and soldering. If you don't have any experience I would suggest a professional.

Works as advertised, not too bad to install

Written by: oTurtlez from Scituate, RI on July 12, 2012

2006 Hummer H3
Crutchfield Customer Review (What's this?)

The installation wasn't nearly as bad as I had anticipated. I just soldered the matching wires, and taped them up and it was good to go. The chime is close enough to the stock one, and my head unit works fine. If I need to buy a new head unit for another GM vehicle, I won't hesitate purchasing another GMOS.

Pros:

Cons:

Weak point of installation

Written by: coachabk from Lake Jackson, Texas on July 4, 2012

2003 Chevrolet Avalanche
Crutchfield Customer Review (What's this?)

Installed this in my '03 Chevy Avalanche. The instructions, as many others have stated, could use some improvement. If I were just installing this harness without the steering wheel control adapter, things would have gone fairly smoothly. However, I had to call Tech Support with a few questions along the was because there is a portion of the harness that looks real similar to the steering wheel control adapter that isn't used. I do which that the harness included a connection to the headlamp circuit that would have allowed the display to dim when the headlamps were activated.

Pros: Plug and play.

Cons: A bit confusing on wiring; no dimmer circuit.

Slow and Unsteady loses the race

Written by: Cd from Anniston AL on June 21, 2012

2006 Chevrolet TrailBlazer EXT
Crutchfield Customer Review (What's this?)

The GMOS for the most part provides an easy interface overall. However, it slows some feedback to the head unit down. Our install was going great till we encountered problems with the parking brake safety, etc. We later determined it was a result of the GMOS being slower than what the head unit was looking for. It's an overall necessity for GM vehicles, but can hinder your install time.

Pros: Makes getting started easy.

Cons: Slow feedback to head unit can paralyze some features

GM Factory Integration Adapter

Written by: sid from schenectady, ny on June 3, 2012

2004 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

I Have installed many decks over the years, thats why i decided to try this my self. The only Issue i had was that most decks have a constant power, ignition power and a ground. The basic 3 wires that have to be hooked up, on the side that hooks to the deck there was 2 Ignition (red) wires. this was a little confusing the instal manual did not say weather to hook up both red wires to the deck ignition. I did anyway and it worked fine. this issue may need to be looked into. it was easy for me because of my history. but for somebody else may not be.

Pros: Easy install

Cons: need to be clearer on install.

GM factory intergation Adapter

Written by: Tyson from queens NY on June 1, 2012

2003 Cadillac Escalade ESV
Crutchfield Customer Review (What's this?)

just what I needed works perfect my radio sounds even louder than before with my same bose system in my cadillac but with a aftermarket radio I still have onstar and all of my chimes. thanks

Pros:

Cons:

Absolute junk. Created DTC's

Written by: Herb from Fort Wayne, IN on May 27, 2012

2007 Pontiac Grand Prix
Crutchfield Customer Review (What's this?)

Would pick zero stars if option. Installed and had no problems for about a week. After that my ABS, BRAKE, traction control and stability control lights kept coming on and going off, multiple times while I was driving. thought it may have been my install error. Double checked everything and it's all good. Removed and put factory back in, cleared all codes and haven't had a prob with the lights since. Trying to bypass the pack and get everything to work and have steering wheel control. Definitely not going to buy from that company again. Will continue to buy receivers from Crutchfield, but probably not much else. Very unsatisfied.

Pros: Never had one for more that a week.

Cons: Set codes and has noise through the speakers.

Installed in my 05 Chevy Tahoe

Written by: BrossHawg from Ephrata, WA on May 22, 2012

2005 Chevrolet Tahoe
Crutchfield Customer Review (What's this?)

This unit works well and does what it is supposed to. I would have given it 5 stars if it were not for an issue I had after installing. The blue potentiometer does more than just turn down the door chimes (which were very loud at the factory setting). If you turn down the door chimes with the stereo on, it also turns down the gain for the deck. I had the system sounding really good and the wife complained of the door chimes being too loud. In a hurry, I adjusted them down and reinstalled the deck and cleaned up (had to leave for a dinner date). After that, the sound was horrible, and I was pulling my hair out thinking I messed something up. After talking to a tech at Crutchfield, we figured out what happened. You have to turn the stereo off for 10 seconds and THEN adjust for the door chimes. Other than that, all is good.

Pros: *Ease of installation *Functions as advertised

Cons: *Directions could be more detailed (see above)

Worked Great! For Pontiac Grand Prix

Written by: Benja from Illinois on May 4, 2012

2005 Pontiac Grand Prix
Crutchfield Customer Review (What's this?)

Worked great with a JVC kw-R500 receiver and the Axxess ASWC steering controls in my 05 Grand Prix GTP with monsoon.

Pros: Worked Great! The warning chimes and Onstar all worked properly and sounded like they were supposed to.

Cons: The directions need to be written better.( until then you can call crutchfield.)

It does what its supposed to

Written by: Michael from Ohio on April 13, 2012

2006 GMC Envoy
Crutchfield Customer Review (What's this?)

I got this adapter for my 2006 Envoy Denali with Bose sound. It does what it says its supposed to integrating door chimes and onstar. I don't use onstar so that was not a big deal. I like being able to adjust the door chime level because even on the normal level with the factory radio they were loud and annoying. The Bose sound quality is not quite as clear as it was on my 2000 GMC Jimmy. Not sure if its because of the adapter or just the speakers. One major thing the instructions dont bother telling you is that when the chimes are not playing the adjustment acts as a gain control. This fixed a lot of my sound issues i was having at first with the distortion as many have stated in their reviews. Still not the Bose clarity i had in my old GMC so I may replace my speakers but doing so will not allow door chimes or onstar if you dont go through the factory amp. Hope this helped a few people. Overall it was easy to set up and Crutchfield is always great with service thats why i keep coming back.

Pros: Easy Set up and adjustments.

Cons: Needs a little more detail in instructions but if you have a little knowledge in car systems you should have no problem

GM wiring harness

Written by: Clint from Leland, NC on March 21, 2012

This is one time you don't get what you pay for. Should have bought the wiring kit from a different retailer for $30 less that comes with the needed antenna adapter. Plus I got tricked into thinking the steering wheel adapter came with it since it shows the harness in the pic. Why would you include that section of harness (that comes with the ASWC unit) if not included??

Pros: What actually did come in kit worked great. Chimes do sound different but I like the new sound better..seem deeper. Like the ability to adjust sound level of OnStar and chimes.

Cons: Over priced and does not include antenna adapter. Instructions are useless since it doesn't tell you what ALL the wires are for, hope you have some install experience. Tells you to connect the red wire of one harness (that actually has two which need to be connected together) to the red wire of after market radio harness. Also says to connect orange and white which is no problem but doesn't tell you that the same color of wire on the other connector of harness ALSO needs to be connected.

Product worked Crutchfield support worked even BETTER!!

Written by: SeanS from Trail BC Canada on March 6, 2012

Seen the previous negative reviews but things worked out perfectly for me. There have been faulty GMOS04 units but Crutch will always exchange a bad one to make you a happy customer. Installed it with a double DIN GPS deck in my 02 grand Am. Monsoon system no onstar. It retained my factory chimes, factory amp, and all functions. I did hit a snag though. After wiring it up it sounded awesome. However, I was only getting audio when the door was open?? The second I closed the door the audio would go mute yet the deck was still running. Open the door and the audio would come back? WTF?? Called tech fearing the worst. No offense but usually tech numbers are dudes reading trouble shooting tips off scripts. It was clear right away that tech knew what they were talking about. Anyways....solution from tech... I hooked the remote wire from the deck to the remote amp on the module, like you would a normal aftermarket amp and it works. Weird considering that remote wire is designed to power an aftermarket amp that I don't even have?? However it solved my problem and now audio works as it should opened or closed doors. In this day and age its extremely rare to be "taken care of after purchase" Crutch's techs came through and assured me if all else failed they would have replaced the item no questions asked. They went the extra mile while on the phone and me in my car troubleshooting.Great product?? That's not why I will be a returning customer. The service is why.Thanks

Pros: worked for my 02 Grand Am as described

Cons: Would agree with most reviews.......the instruction manual for is terrible!! Tough to follow

2003 Yukon with Bose

Written by: Dave from Woodbury, MN on February 24, 2012

I was a little nervous about buying this due to the number of negative reviews, so I thought I would share a positive experience. I installed this last night into a 2003 GMC Yukon with the premium Bose and Onstar; however, I do not use Onstar. Everything worked perfectly at the first test. I had no issues with buzzing, distortion, dead battery, crappy sounding chime, not shutting off when I open the door, etc. While the step-by-step instructions were easy to follow, I agree with the others that said it would be nice to have a wiring diagram included. Also, there were no instructions for adding the ASWC. The ASWC part wasn't that difficult to figure out, but it would be nice to have some sort of validation prior to plugging it in. In my opinion, this product deserves 4 1/2 stars, since I believe the functionality far outweighs the mediocre instructions. However, since there are no half-star increments, I am giving it 5, because I am very pleased with how this works.

Pros: Works great!

Cons: No wiring diagram or ASWC integration instructions.

So far so good

Written by: Lawrence from Long Island NY on February 22, 2012

2007 Chevrolet TrailBlazer
Crutchfield Customer Review (What's this?)

I needed this unit to install a new Pioneer AVH-P2400BT in my 07 TrailBlazer SS . It is working fine so far , my only complaint is that the instructions aren't very good. They don't even explain what every wire on the unit is for. The folks who write these manuals should really learn how to explain all aspects of their product in a simple manner.

Pros: You need it to retain your door chimes and Onstar

Cons: You need it to retain your door chimes & Onstar. Instructions stink.

Pretty Easy

Written by: CSP from Inver Grove Heights, MN on February 8, 2012

Way easier than I thought. This was my first install ever. Worked great with my 2006 Chevy Crew Cab with Bose and Onstar. Instructions were somewhat clear but I easily figured it out. All harness fit to perfection and it did exactly what is was supposed to do. Had to call and ask a few questions but that was expected.

Pros: Everything works Retained Onstar and factory door chimes Worked with current Bose 7 speaker setup Has adapter for steering wheel control built in (unit sold separately)

Cons: Door chime sounds a bit different A little intimidating at first

Adapter kit

Written by: Joseph from Texas on February 6, 2012

2006 GMC Sierra 2500/3500
Crutchfield Customer Review (What's this?)

Product works. Little slow on the reaction to the chime. That may be in part to the Bose amp.

Pros: Plug and play.

Cons: Size. Excessive housing make it difficult to place in the confines of the dashboard.

Doesn't Work as Advertised for the Corvette

Written by: Mike from Texas on January 27, 2012

2006 Chevrolet Corvette
Crutchfield Customer Review (What's this?)

I installed this to go with my Kenwood DDX 418 and it worked fine when using On Star but it failed in retaining the factory chimes. I ended up with a loud constant whine that was nothing like the factory tones. I took it off and installed the PERIPHERAL module in lieu of the GMOS-04 which resulted in the factory chimes and the On Star interface that I was looking for. I did my research in the audio section of various car forums and those who recommend the PERIPHERAL unit stated that it has the Delphi chipset and GM uses Delphi for their electronics so there is no issue with losing your factory tones or use of On Star. I would recommend researching on various electronics forums and read the testimonies of others who have tested the product instead of read the staff and consumer reviews on this website. Nothing against staff or the fellow customers who have bought this product as I have benefited from such reviews. I'm sure they have done their due diligence but if you are going to invest a lot of time and money to install an aftermarket audio system, you owe it to yourself to do the research so you can make an informed decision. Even after reading this, please look at other sources to do your research so you know you are going into the installation venture eyes wide open.

Pros: There are none. Perhaps reading this review and going with the PERIPHERAL unit will be the positive.

Cons: For the Corvette you lose your factory warning sounds.

GM BOSE Factory System Integration Harness

Written by: Owen from Texas on January 20, 2012

2005 Chevrolet Tahoe
Crutchfield Customer Review (What's this?)

The product arrived in brand new condition. The product included detailed instructions of installation. It also had technical support via phone.

Pros: Very simple to install and it works really well. It does everything it claimed to do.

Cons: It is quite large, had trouble getting all of it in the dash board space behind the radio. It doesn't work with the steering wheel volume control. That's a big down side loosing the capability to control the volume from the steering wheel.

Piece of junk

Written by: Matt from Frisco, TX on December 26, 2011

Crutchfield Customer Review (What's this?)

Installed along with JVC KW-XR610 unit in '04 Tahoe. Tested everything - worked great. However, within an hour of installation, car battery was completely dead. Stranded my wife out on the road. Started reading the reviews on this thing...sure enough, others having the same issue. Asked Crutchfield tech support guy about PAC brand and said the GMOS is actually what they've had the most success with. (Doesn't exactly inspire confidence). They are sending me another one to try. If this one doesn't work I'm sending it and the JVC unit back. Keeping my fingers crossed.

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Metra GMOS-04 Wiring Interface

Written by: Bernard from Chicago on October 6, 2011

2004 Chevrolet Tahoe
Crutchfield Customer Review (What's this?)

The trickiest part of the system install but the support team was extremely helpful. After 30mn on this particular product, everything was up and running. Thank-you

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Simple Connection, Inexpensive

Written by: kinukawa from Petersburg, VA on September 23, 2011

2005 GMC Sierra 1500
Crutchfield Customer Review (What's this?)

The Axxess GMOS04 adapter and Steering Wheel control adapter (PAC-SWI- JACK) were required for application on my 2005 GMC Sierra w/ Bose and were relatively simple to hook-up. Slightly different sound from original warning bell - smoother tone. I did not have to adjust volume for Onstar or bells and I was using 4V pre-outs... not sure why people are having issues w/ that? Miscellaneous steering wheel-control wires (red/black mic-type jack) and Onstar harness that aren't covered in the instructions are unnecessary in 2005 GMC Sierra using PAC's SWI-JACK. Took about 4 hours and I was taking my time with everything. Quoted over $600 for same work from an independent stereo shop because it was "tricky work"...over 50% savings and no headache.

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Metra GMOS-04 Wiring Interface

Written by: ChvyBoy from Columbus,Ohio on September 17, 2011

Crutchfield Customer Review (What's this?)

First off fast shipping, ordered it on Wednesday afternoon got it Friday. At first it seem complicated. But after reading the instructions it was as easy if not easier than hooking up a regular harness cause you don't have all the wires to match up. The door chime does sound different. But I don't mind it and I like the fact that you can change the volume of the chime. I have a Trailblazer with Bose system and I installed a Pioneer Double Din. I don't know if it was cause of the harness and the way its hook up or what but my speakers sound way better now than it did with factory deck. 5 stars all the way and worth the price. Don't let someone cheat you out of having you door chimes, onstar and amp.

Pros:

Cons:

confusing

Written by: pj from Richmond, VA on August 15, 2011

Crutchfield Customer Review (What's this?)

Very confusing installation manual. There are specific instructions for the Corvette and the wire colors and labels made it even more confusing. Just expect to be on the phone with the techs on this part of the installation. Otherwise, everything works.

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Metra GMOS-04 Wiring Interface

Written by: Howie from apple grove WV on August 10, 2011

Crutchfield Customer Review (What's this?)

simple instructions easy hookup after the adjustments brings out a good sound and keeps the factory accessories working like they should

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Don't install without this

Written by: Tim D from Woodbury, MN on August 2, 2011

Crutchfield Customer Review (What's this?)

Made the install straightforward and worked perfectly. OnStar, Bose and Chimes all worked great without any adjustment. Only complaint is my 4 volt pre-out deck clips the interface, but I am installing a Boston Acoustics outboard amp so that will no longer be an issue. Thanks Crutchfield!

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Metra GMOS-04 Wiring Interface

Written by: Angel B. from California on June 11, 2011

2000 Chevrolet Impala
Crutchfield Customer Review (What's this?)

I installed it in my 2000 Impala and it was terrible I had to bypass the RCA hookup and the door chimes are barely noticeable. I don't recommend it, its not worth the price. I gave it one star but it really needs no stars.

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Great product and support, terrible instructions

Written by: JimK from Southern Maryland on May 15, 2011

2004 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

This product works as advertised to integrate an aftermarket receiver into a GM premium or Bose system. The instructions are not very good. No diagram and there were undocumented connections for the steering wheel control unit. Crutchfield cost on this was only half-price with the receiver order. Not sure if that was a special or standard offer. IMPORTANT NOTE: You will also need a Metra Access ASWC in addition to this control unit to activate the steering wheel controls. So you need both units to get full functionality. Crutchfield tech support was helpful here but it should have been more obvious when I placed the order.

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Metra GMOS-04 Wiring Interface

Written by: JohnQ from Chicago on May 14, 2011

2003 Chevrolet Tahoe
Crutchfield Customer Review (What's this?)

It's expensive but you won't be able to do the job quickly without it. Installed in a 03 Tahoe with Bose with no problems. It retains the car chime over the speakers and lets you use your Bose speakers normally. Sound quality is really good.

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It worked for me.

Written by: Keith L. from Utah on May 12, 2011

Personally, once I found out what the blue antenna signal wire was for, I felt the whole system works flawlessly (or almost). Many people from other reviews I have read complain about how the door chimes sound and that they sound like a toy. Well, I feel the chimes sound almost exact to my original door chimes that were factory installed. The only problem I have with that is...while there is no engine interferance with the sound coming from the newly installed stereo, there is noticeable interferance while the chimes play. Currently, I am not sure what I can put in place to filter out the engine noise for the chimes only so they sound crisp and clean and not affect the sound of the stereo. My only other frustration with the unit is, as other reviewers mentioned, the chimes are extremely loud. I had to turn the small volume control down to almost off in order to get the loudness to a level I was comfortable with. It does maitain the power to the my new unit after the key has been turned off. I don't think it holds it as long as the original 20 minutes that the car was installed with. But then, I don't ever sit in my car longer than that with the key turned off. Basically the unit performed as described. Wires were marked well. It was pretty self explanitory.

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No chimes, well almost

Written by: Marshall from NC on May 3, 2011

2003 Pontiac Grand Am
Crutchfield Customer Review (What's this?)

The chimes seem to be the same tone, or close enough if they aren't. The problem is they are so soft that you won't hear them with the radio on. I contacted Crutchfield support who said there was nothing they could do. The radio works so they consider the product to be fine. I contacted Metra and they seem confused as to whether or not I turned the volume all the way up or not (I did of course). That's why I gave it two stars. The chimes are THAT important in case of problems. Otherwise the box is perfect if you read the instructions, have the right adapter, and check your wiring. Hooking it up to a Monsoon or similar amped system is quite easy. Sit down at your kitchen table and wire the adapter to the radio first. Then when you get to the car you just plug it all in and enjoy the music.

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Disappointment

Written by: andy from indianapolis, IN on April 26, 2011

I bought this with a new pioneer head unit for my 01 grand am w/ monsoon sound system. i installed it and the sound was very quiet and distorted. There wasn't an even balance of sound. the front driver side speaker could barely be heard and the rear speakers were way louder. after five minutes of listening to the radio it completely shut off. I checked all connections and it wouldn't work, so i rewired everything and it wont even turn on now.

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didnt work but Crutchfiels made it right

Written by: Anonymous from Greenville SC on April 21, 2011

2004 Chevrolet Tahoe
Crutchfield Customer Review (What's this?)

Wired up the product and the chimes didnt work. Front speakers didnt work. Spoke with Tech and did some tests and they immediatly sent out new product. Plugged it in and all worked perfectly. 2nd one worked great

Pros:

Cons:

Metra GMOS-04 Wiring Interface

Written by: andym from indianapolis, IN on April 20, 2011

2001 Pontiac Grand Am
Crutchfield Customer Review (What's this?)

slightly hard to hook up if its your first car radio install.

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Thank Goodness

Written by: RogerF from Midwest USA on March 28, 2011

2002 Chevrolet Impala
Crutchfield Customer Review (What's this?)

If you have GM's class II databus, then you may know it can be complicated to integrate a new radio to your vehicle. This device makes that integration a plug and play process. If you are handy with hand tools and comfortable with wiring then this will make your installation a breeze!

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Cons:

Metra GMOS-04 Wiring Interface

Written by: Jeff from Forest Hill, MD on March 24, 2011

Crutchfield Customer Review (What's this?)

If you have a GM this is a must. Clear install instructions, works great.

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Cons:

Metra GMOS-04 Wiring Interface

Written by: WayneN from Minneapolis, MN on March 14, 2011

2003 Chevrolet Monte Carlo
Crutchfield Customer Review (What's this?)

This adapter worked as it stated to support the amplified bose factory system and chimes in my 2003 Monte Carlo. After adjusting the audio screws on the circuit board for sound output, I was able to get the sound to my liking. It all worked great and was easy to install. Other brands of harnesses I looked at required multiple harnesses to support all the features of this one and were much more expensive.

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Metra GMOS-04 Wiring Interface

Written by: Anonymous from Corinth, ME on March 8, 2011

Crutchfield Customer Review (What's this?)

makes for an easy hookup, but the door chime is almost inaudible

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Does What its supposed to do

Written by: KJr from Galesburg,IL on February 24, 2011

Crutchfield Customer Review (What's this?)

It worked like it was supposed to. The only problem I had was forgot to hook up one wire and a call to customer support, cleared that up for me. Would buy again.

Pros:

Cons:

Metra GMOS-04 Wiring Interface

Written by: dc from Huntsville,AL on February 17, 2011

2003 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

This adapter works well if it arrives functional. The 1st one sent with my order had a bad channel on it. After doing some research on the internet, it seems that there is an unacceptable probability that you'll get a defective unit. Crutchfield was great with the return and sent a new one out immediately... so +1 for their customer service. The 2nd unit worked out of the box and so far so good.

Pros:

Cons:

Metra GMOS-04 Wiring Interface

Written by: buckfever5 from Illinois on February 13, 2011

2003 Chevrolet Silverado 1500
Crutchfield Customer Review (What's this?)

Quick and easy install in my 2003 Silverado. I spliced the deck harness to the GMOS in the house before I pulled the factory head unit out. Once I pulled the factory head unit it was smooth sailing. I was a bit concerned about where the GMOS unit was going to go in the dash, but there's plenty of room behind the head unit to tuck it out of the way. Everything works as it should. The door chimes have a different tone, but it doesn't bother me.

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Ok but a little dissapointed

Written by: LP from Green Bay, WI on February 12, 2011

2005 GMC Yukon XL
Crutchfield Customer Review (What's this?)

Ok just to be straight, this actually works just the way it is supposed to and the instructions were easy to follow even for a first time installer. What I'm dissapointed about is that I lost the audio for my factor installed DVD Entertainment system in the back. Crutchfield had a disclaimer before I bought this saying that I would so it's not their fault. What I'm dissapointed about was that right after I bought and installed it I found out from one of Crutchfield's suppliers that the new GMOS-14 which would have given me this option was only weeks away from shipping to them. Even though it's not available on line it is in the test phase and it would have been nice to know that it was out there. Now I have to go through the trouble of pulling everything apart when it does become avaialable on-line. The nice thing was that Crutchfield told me that if/when it becomes availalbe on line to call back and they'll work something out, either as a one for one trade in or just paying the difference if the new one is more expensive. So Kudo's to Crutchfield for that. You guys are ok in my book, just give me a little heads up next time.

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Did not work

Written by: Paul from Illinois on February 7, 2011

Crutchfield Customer Review (What's this?)

Installed and had crackling in speakers. It took a while to trouble shoot what was causing this, ended up replacing with a PAC OS2 harness and now works fine. Crutchfield did refund my $ on this return. Thank you Crutchfield.

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Not sure on this item yet

Written by: Mike C. from New Orleans, LA on February 4, 2011

I purchased this device to tie my Clarion into my '06 Tahoe. Wiring was straight forward and relatively easy to lay out on my workbench with both sets of instructions (this device and the radio). My problem with it is that there is a variable resistor that controls the output to the radio and increased/decreased your volume output. Initially I would crank the radio up all the way and not get the volume I used to get, and no, I was not playing it at a deafening level. I have found, maybe it's the radio but I doubt it, that my sound level is simply not as robust now as it was once and since I'm feeding out to the Tahoe's OEM Bose system, I would think I would get the same, if not better sound and volume, but I do not. What the cause is yet, I'm not totally sure.

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Need to go back to the drawing board GM

Written by: bkenner from SC on January 31, 2011

Crutchfield Customer Review (What's this?)

This product is completely unsatisfactory. Causes severe distortion. In my 04 Yukon application, tech support couldn't determine fix. Don't waste your time or money. Problem lies with complex GMC system. I gave up and returned entire GMOS and head unit package and stuck with stock GM radio - bummer.

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Metra GMOS-04 Wiring Interface

Written by: BartK from Houston, TX on January 27, 2011

2003 Chevrolet Tahoe
Crutchfield Customer Review (What's this?)

Easy to install. 2 orange wires on 1 harness through me of though, instructions didn't specify to connect both from that harness to 1 orange wire on the other harness, but a quick call to Crutchfield support solved that.

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Worked like a charm - 2006 Chevrolet Trailblazer LS

Written by: SullyCuse from Sugar Hill, GA on January 4, 2011

Worked like a charm. Used this with a new Clarion CX400 Head Unit in my 2006 Chevrolet Trailblazer. I do not use ONSTAR, so not sure if that works or not, but all the chimes work, as well as the delay shut off of the unit until the door is opened after turning off the ignition! So with everything else working, I am assuming the ONSTAR is still functional. Directions were concise and very easy to follow. Hooked all the wires up to the head unit wire harness in about 20 minutes. Then just a matter of plugging into the existing harness in the vehicle! Sound is fantastic and retains the BOSE amplifiers located on the speakers. 100% recommend this for any vehicle with existing ONSTAR and BOSE speaker set up!

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Metra GMOS-04 Wiring Interface

Written by: Anonymous from austin, tx on December 2, 2010

Crutchfield Customer Review (What's this?)

great product. heard all kind of reviews on it and was a little worried about the install. they were all wrong. took no time to install & worked like advertised. soud was great & did not even have to adjust output level or door chime volume. installed it in a 2003 chevy suburban. used a pioneer avh-p3200dvd.

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Metra GMOS-04 Wiring Interface

Written by: BMH from Illinois on November 29, 2010

Crutchfield Customer Review (What's this?)

Installed this unit in my 2004 Silverado with Bose Speakers and Pioneer FH-8000BT. Unit works good with Onstar. It sounds like chime noise comes through the speakers now which sounds a little different but there is an adjustment to turn it up or down. I turned mine down enough that I can hardly hear it and it's not an issue. Instructions were good and easy to wire up.

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