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Axxess GMOS-100 GM Factory Integration Adapter

Connect a new stereo and retain OnStar®, Bluetooth®, factory amp, warning chimes, and steering wheel controls in 2000-up GM vehicles

53 Reviews

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Item # 120GMOS100

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Our take on the Axxess GMOS-100 GM Factory Integration Adapter

You want to install a new car stereo in your 2000-up GM vehicle, but you don't want to lose useful factory functions. Thanks to this Axxess adapter, you can upgrade to the higher sound quality of an aftermarket receiver while maintaining your factory-installed satellite radio tuner, OnStar®, Bluetooth®, factory amplifier, and steering wheel audio controls. In some vehicles, you can also retain your factory rear seat entertainment system and your GM backup camera. All harnesses are included, and this interface works with both amplified and non-amplified GM factory systems.

You want to install a new car stereo in your 2000-up GM vehicle, but you don't want to lose useful factory functions. Thanks to this Axxess adapter, you can upgrade to the higher sound quality of an aftermarket receiver while maintaining your factory-installed satellite radio tuner, OnStar®, Bluetooth®, factory amplifier, and steering wheel audio controls. In some vehicles, you can also retain your factory rear seat entertainment system and your GM backup camera. All harnesses are included, and this interface works with both amplified and non-amplified GM factory systems.

The package includes the GMOS-100 module, the 22-pin to 30-pin GMLAN29 harness, the 22-pin to 30-pin GMLAN1 harness, and the 22-pin to 24-pin CLASS II harness. The package also includes the16-pin backup camera harness and the 16-pin rear-seat entertainment system harness, but you can only retain those features in GM vehicles compatible with the GMLAN29 harness (see the Details tab for compatibility chart).

Installation Note: If you plan on keeping the GM satellite radio tuner and your GM vehicle does not have a Driver Information Center screen, you'll need to buy a separate dash-mount screen to display satellite radio and iPod info.

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.

Product Highlights:

  • works with GM vehicles with the CLASS II, GMLAN 11, or GMLAN 29-bit data systems
  • works with amplified and non-amplified systems
  • also allows you to retain GM satellite radio tuner in select models
  • retains rear-view camera and rear-seat entertainment system in select vehicles (new receiver must have camera input and RCA inputs)
  • warranty: 1 year
  • Our 60-day money-back guarantee

What's in the Box:

  • GM Steering Wheel Control module (GMOS-100 interface)
  • 4-pin to 4-pin resistor pad harness (LD-GMOS100RPAD)
  • 22-pin to 30-pin LAN 29 wiring harness (LD-LAN29-100-2)
  • 22-pin to 30-pin GMLAN 11 wiring harness (LD-LAN11-100-2)
  • 22-pin to 24-pin Class II wiring harness (LD-CL2-100-2)
  • 16-pin Backup camera harness (with composite video RCA connector)
  • 16-pin RSE harness (LD-GMRSAV)
  • 16-pin harness with stripped leads (LD-2NAVAMP)
  • Female 3.5mm harness (LD-SWC-F3.5)
  • Resistor (tucked in manual)
  • Instructions

Axxess GMOS-100 GM Factory Integration Adapter Reviews

Average Customer Review(s):

(53 Reviews)

Great Product

HarleyMan00 from Three Springs,Pennsylvania on 7/9/2013

The Staff At Crutchfield Said this is what you need to not lose anything working on your steering wheel and onstar and yes they were right again!

Pros: The kit made everything work and save a lot of time and mistakes.

Cons: There were a few packs of wires i pay for that did not need to be in the kit for my Vehicle but would have been needed for other vehicles!

Axxess GMOS-100 GM Factory Integration Adapter

Miguel from Miami Florida on 6/19/2013

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

It was easy to install. However my steering wheel control are not working. I was under the impression that this interface will make it work. I was told that I need another part to make it work, more money to spent. It would had been good to know this before hand.

Pros: Speed pulse reverse signal was included in the plug wires. My radio is working as designed.

Cons: Steering wheel control not working do to it needs another connection Even in the package it states it maintain steering wheel function.

AXXESS - not fun

Craig RLC from Atlanta, GA on 6/19/2013

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

it works for right now. Had one heck of a time getting it set up to where it worked with the steering wheel. Assembled and disassembled, called Crutchfield at least a dozen times and when I did get it hooked up then the OEM chimes for the door open, key in ignition did not work. The volume was a bit touchy to get adjusted and I did have to take and hook to computer to download updates and that seemed to clear things up. The manual that comes with the module is not very specific as to what where all the wires go and to what wire but again the Crutchfield folks where there to keep me sane during the process. One of the techs did give me some great advise as to hooking up the harnesses: don't do it in the vehicle but do it where you have plenty of light on a table, work bench whatever. The colors and the striping on the wires are not always easily identified.

Pros: none - it worked finally so I guess that is a pro.

Cons: not really any other alternatives.... not easy to follow-instructions.

Piece of junk

MJB from MA on 6/14/2013

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

Installed in my 04 GMC and lost my rear speakers. I wired it first as having a factory amp (which I do) and then pulled the resistors, and still no sound. Speakers work fine with factory radio. Turning the potentiometer up just gives you more white noise than already exists. In hindsight, I would have lived without my steering wheel controls and not wasted my money on this. It worked out for Crutchfield though as I then went and bought and aftermarket amp and speakers to remedy the situation.

Pros: Once you program it right after attempting ten times, you retain steering wheel controls.

Cons: Overpriced piece of junk.

Wiring harness

Case1079 from Freelandville on 6/10/2013

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

Easy harness to wire, works great

Pros: Able to maintain steering wheel controls,

Cons: Door chime isn't very loud, had an issues with my factory XM radio bleeding over onto my head phone for rear entertain system, but the awesome tech support was able to help me fix that issue

Axxess GMOS-100 GM Factory Integration Adapter

Mike N from Sandwich, Illinois on 6/3/2013

Crutchfield Customer Review (What's this?)

Worked pretty much as advertised. I would like to see a more application specific kit as I have no use for most of the wiring looms that came with it. Either that or a way to return the unused portion for credit. Regardless, the install was easy to do with some time spent soldering and a few head scratching "HUH?" moments before the light bulb went off....

Pros: Instructions

Cons: Alot to discard

Works like a charm!

Michael from Bethlehem, GA on 5/28/2013

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

Not a bad little device! Slightly difficult to understand the instructions and some of the steps even had the phone techs head spinning. Not in the instructions but needed to disconnect my factory XM receiver as it and my DVD player were competing for the IR signal. My DVD player is more important for my boys. All and all a decent little unit plus I have extra harnesses in case I upgrade to a newer 'Burb.

Pros: Small and easy to slip into the tight spaces

Cons: Wiring harness looks scary but really isn't. Loss of rear seat controls.

Decent Wiring Harness

damonl from Park City, UT on 5/24/2013

Crutchfield Customer Review (What's this?)

This wiring harness was installed in a Chevrolet Suburban. I did the job myself, although I did have to call Crutchfield Tech Support a number of times. The directions skip around and they fail to mention that on GM's you are more than likely going to have to connect the Parking Brake Wire and the Foot Brake directly to the GM wires and bypass the connections on the CMOS 100. Once I hooked these 2 wires up direct everything worked like it should. Not a big deal really I just thought I could save some people the hassle.



GMOS Factory Integration adapter. ++

Shawn from New Hope, MN on 5/20/2013

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

I have installed several car stereos over the years. I thought it would be easy. But once I got the dash apart it became clear to me that I may need help. After reviewing the directions I decided to let the experts install the radio. This unit worked great. The only downside was that the Installer didn't catch that two wires on the GMOS needed to be connected to each other with a 3rd wire that was included. The professionals typically use the GMOS 40 so they were not 100% familiar with the 100 unit. After getting the car back I had a little Static. I took the car back in and they troubleshooted online to figure out they needed to connect these two wires together to stop the hissing.

Pros: Works Great

Cons: Maybe a little better instructions.

good product

knilator from louisiana on 5/19/2013

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

Product does everything as advertised simple to install and works couldn't ask for anymore than that

Pros: Simple and effective

Cons: Alot to stuff in the dash but will fit

Axxess GMOS-100 GM Factory Integration Adapter

Jeremy from Reading pa on 5/12/2013

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

Made install easy



Axxess GMOS-100 GM Factory Integration Adapter

Anonymous from Iowa on 5/12/2013

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

worked perfectly. easy to install, just follow directions.

Pros: Worked as it said it would.

Cons: none

Not fun!

Anonymous from Rougemont,NC on 5/12/2013

Crutchfield Customer Review (What's this?)

The instructions for this are horrible. They were very vague! Glad Crutchfield was there to help.

Pros: Keeps the factory features in truck working properly

Cons: Instructions Expensive

it works

Tony from nc on 5/11/2013

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

Used with alpine reciever. works great, just take ur time an call tech support as questions arise. I called twice for about 2 minutes each.

Pros: Works

Cons: No door chimes, but I like it better without them. ha.

It Works

royl52 from Winchester,Va on 5/6/2013

Crutchfield Customer Review (What's this?)

You best be ready to tackle this with a clear head!!

Pros: After a call or two It works, OnStar and steering wheel controls work like before.

Cons: A lot of waste with all the wasted harness choices, bet over 3/4 of the price of the kit is never used and this due to a all in 1 kit, But it works but what a waste of money when you see the left overs. And you must follow the set up step by step and keep all the paperwork you will need it someday.

Worked for me

Jeff53 from Winchester, VA on 4/29/2013

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

This was installed in a 2005 Avalanche with Bose system. I see from the reviews that there's a lot of hit or miss with this product. Mine seems to work OK. All of my steering wheel controls work. In the first week after installing it, I had the front speakers stop working on two separate occasions. After turning off the head unit and turning it back on, the speakers worked again both times. That hasn't happened again in the last month, so I'm keeping my fingers crossed as I wouldn't relish having to dismantle everything again. I didn't have any problems making all of the correct connections, but I can see where it might be difficult if you're not used to wiring things. It would probably be better to just have specific units for the type of vehicle you have. Mine is the older Class II system, so the wiring was fairly straight forward, but you are left with a big bundle of wiring that you don't use and have to find a place to stuff everything behind the dash. I didn't want to cut off the unused wires in case it didn't work correctly and I had to send it back. I'm happy with how everything works at this point, although I can't go forward and backward on the sources (Tuner/XM/USB, etc) like I could using the factory stereo with the steering wheel controls, but I think that's more a function of the new head unit, since you can only go through the source menu on it in one direction.

Pros: Works. Relatively easy to install if you're used to wiring things. Allows you to retain all of the factory functionality.

Cons: Tries to cover too many different systems, leaving a lot of wiring unused which can be confusing. Doesn't seem that sturdy.

Axxess GMOS-100

Harry from Queens, NY on 4/28/2013

Crutchfield Customer Review (What's this?)

I purchase a Pioneer AVH-P8400BH to replace my factory Bose unit in my 07 Chevy Trailblazer, so I had to get the Axxess GMOS-100 to keep the onstar and the door chime, also wanted to keep my steering wheel button functions. The Axxess GMOS-100 made connections easy, basically plug and play. Work great, no splicing, just plug ins.

Pros: Easy hook up, works great.

Cons: none yet

Pretty Chincy

Manley from Colorado Springs, CO on 4/20/2013

2008 GMC Envoy
Crutchfield Customer Review (What's this?)

I hate how there is very little in the ways of options for stereo integration. They always seem cheep and the quality control on the products seem to suck. The first one I recieved, after trying to figure out the muddled instructions, ended up being faulty. So not only was there about 3 wiring harnesses that came with it that were not used, it didn't work. Even after updating the firmware to the product, nothing. So after talking to Crutchfield, they sent me a New one. I didnt have to immediately return the old one (as there was SOME functionality) until the new one arrived and worked. So overall, product was hit or miss, but Crutchfield's customer service was and is outstanding. I highly recomend buying headunits from these guys.

Pros: All functionality worked after the 2nd go.

Cons: Product has stupid instructions, vague and confusing and comes with way too many things that you dont need and doesnt really explain which one you DO need. Also horrible quality control as I needed to replace mine immediately to get one that worked properly.

Didn't work in my AV Z71 1500

Anonymous from Lexington, SC on 4/17/2013

Crutchfield Customer Review (What's this?)

Got everything hooked just to have to disconnect everything because it was faulty

Pros: None

Cons: Didn't work


jason from la junta, CO. on 4/16/2013

Crutchfield Customer Review (What's this?)

Lost control to factory dvd player, crutchfield advised me that would happen. Had to call tech support when installing. Directions not too clear.

Pros: Several options

Cons: Is not easy to install, difficult directions. Had to guess at certain points.

Ok Product

C.J. from San Diego, CA on 4/10/2013

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

I purchased the GMOS to retain the use of my ONSTAR and chimes in my 2005 GMC Sierra SLT. The GMOS-100 does allow you to keep your ONSTAR and chimes. My first install of the GMOS had dismal success with chimes working until the ignition is switched off an on again.Then I would have to do a reset with the same results. CRUTCHFIELD TECH Support informed me that there was an update needed to correct the problem. Though my chimes work at times they are intermittent, while testing the system with keys in the ignition after about 15 to 20 sections they stop. I have to wiggle to key to get the chimes to return. The directions are vague to say the least and in my opinion not properly written. No where in the directions did I see information informing me of updating the GMOS to the latest firmware. In order to update the GMOS you have to have a micro USB, if your like me you may not have one. This should be included I had to shell out $. Along with that I have cables that are not needed for my truck, witch made it much more difficult to determine witch wiring hornist was needed. Thanks to Travis in tech support I completed the task. While uninstalling my JVC unit for the 4th time on 4/10/13 the needed firmware was down, on AXXESS web site witch cost me time. Overall it serves it's intended purpose.

Pros: Retain ONSTAR, and Chimes.

Cons: Vague and hard to follow Instructions, Micro USB not included, Chimes work not as I expected.

Absolutely aweful

EvanD from Birmingham, AL on 3/30/2013

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

Door chimes don't work. Instructions are written like they are "reminders" for someone who has installed one of these before. Thanks to crutchfield support I was finally able to finish my install. This adapter also cost me my spare blue 15 fuse :(. Also I can't figure out how to program steering wheel controls so I guess Im stuck without those either.



Works Great, not for beginners

James S from Killeen, TX on 3/28/2013

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

This harness works great and made it easier to use just this one set other that the 2-3 different harnesses listed in the article for replacing my 03 Silverardo factory stereo. I'm an helicopter electrician, so having to mess with all the wires was not a problem, but may be a little overwhelming for a beginner. The instructions lacked a little clarity of what parts of the harness you would need, would have been a little easier to say at beginning of vehicle selection, you will need parts, 1, 2, 3, etc.

Pros: Retains the use of steering wheel controls and vehicle chimes.

Cons: Didn't automatically identify vehicle - 03 Silverado, unable to completely remap steering wheel controls per directions, directions could be a little better organized.

Kickin' product

Eric from Santa Rosa nm on 3/27/2013

2006 Hummer H2 SUT
Crutchfield Customer Review (What's this?)

This set up is great. Kept all my features functioning as if the after market stereo came out of the factory in my vehicle.

Pros: Kept all my features functioning including rear entertainment and steering controls.

Cons: The instructions could be a little more detailed. Really vague. Comes with 3 different harnesses and isn't specific on which one is the one u need. Price is an issue but it's still worth it!

Wire Harness

Jspang23 from Peru, IL on 3/20/2013

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

Works good better than a cheaper wire harness

Pros: No need for separate steering wheel interface

Cons: Confusing instructions and more complicated from older models

Tricky to install but works well in the end

Jeff from Cleveland Ohio on 3/18/2013

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

This device is a challenge to install so read everything carefully before you begin. I suggest updating firmware of the module online before you even attempt to install. Once you begin installation and have removed the factory radio be careful to not create faults on the can bus by turning the key or pulling a fuse. If you cause a fault and do not clear it before installing the module you will lose some functionality such as vehicle chimes or steering wheel controls. If this happens, remove the unit, clear the faults and re install. If you do everything correctly this module works excellent!

Pros: Maintains all factory functions

Cons: Tricky to install, not for a beginner

Axxess GMOS-100 GM Factory Integration Adapter

Anonymous from friday harbor, wa on 3/17/2013

2004 Chevrolet Silverado 2500/3500
Crutchfield Customer Review (What's this?)

Good unit if it works

Pros: works as stated

Cons: took 2 units to get one that works

It works and does the job not for the novice installer

Andrew from Iowa on 3/11/2013

Crutchfield Customer Review (What's this?)

Read the instuctions hooked up per them and had to call for support. If you have a vehicle with rear dvd entertainment call the awsome folks at crutchfield support and they can walk you through the re-wire it was pretty easy install overall and works great

Pros: Does the job love having the steering wheel controls still working

Cons: A lot of extra harnesses with unit had to to some reading and research to figure it all out. Not for the first time installer you will get lost for sure

Crutchfield is Awesome! Instructions are not.

Devin from Dallas, TX on 3/4/2013

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

I am glad there is an adapter to help retain all of my cars factory features and once install this unit performs well. I have a 2005 Chevrolet Trailblazer and this adapter helps my aftermarket radio boost my factory Bose stereo system much better than my OE head unit. The instructions are horrible. There is no way to tell which harness you need to use, so of course I had to call Crutchfield. They were very helpful. I didn't anyone could tell me how to do wiring over the phone but they helped me flawlessly. My only complaint is that I lost my factory chimes. They work after I unplug the battery on car and reconnect but no for long.

Pros: Retains my rear entertainment center, Bose sound system, steering wheel controls, and Onstar

Cons: Chimes don't work

Crutchfield response on 3/13/2013 An update to the GMOS100 should give you the chimes. Go here: Download and install the web updater. Connect the GMOS100 brain to your computer with a USB cable to perform the update.


jcast from Arizona on 2/1/2013

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

First of all I want to give credit where credit is due. The tech support staff from Crutchfield is simply the best I have ever dealt with. Thank you, Crutchfield! Everything seemed to work as advertised except my warning chimes on my 2004 Chevy Tahoe which worked at the beginning but stopped working altogether after a few seconds. They would work again initially after disconnecting the module for a spell and reconnecting but would stop, again, after a few seconds. I then was advised to call Metra (their tech support was fantastic as well!) but after resetting the module and going through the initializing process and a couple of other mods it was to no avail. No chimes! I called Metra again yesterday and spoke to Justin. Justin told me that a new firmware update had just come out for testing and he forwarded the two files to me and Metra's link to downloading the Axxess Updater. The downside to this was that I had to dig out my old Windows XP platform PC, dust it off, and hook it all up since my Mac was not compatible with the Updater file. I also had to buy a USB to Mini USB cable so that I could interface with the Axxess module. Following the prompts exactly I successfully updated the firmware from 1.6 to 1.7. Guess what? My chimes are working for me and my Pioneer AVH-P3400BH sounds fantastic!!!! All is good and the world is right again.

Pros: It works now as it should have all along on my 2004 Chevy Tahoe. Crutchfield and Metra Tech Support were awesome!!

Cons: Frustrating. Glitchy. USB CAB cable not included in kit. (Metra, please add the cable to your kits!) You have to have a USB to Mini USB cable to interface the module with your PC platform computer. You need patience.

Again - read the instructions

JM from MT on 1/28/2013

Crutchfield Customer Review (What's this?)

If you're not familiar with the saying "10lbs of crap stuffed in a 5lb box", you will be. This was installed in a 2007.5 Chevy Silverado truck with a JVC head unit and a new Sirius receiver; all from Crutchfield. I had to cycle the power a few times to reset the computer and get it all to sync up properly with the turn of the ignition but it all works as it should so far. The instructions really are vague. They are written with assumptions and small details that are easy to miss. Prior experience and careful reading comprehension are what saved me. IMHO they are written with the professional installer in mind. I took the truck apart and made a plan of attack before I started soldering wires together and I still wish that I would have added a little length to one of the harnesses. Four stars because it actually worked. Crutchfield's advisers from point of sale to tech support did a fine job. It took me 7hrs from start to finish.

Pros: It works like it says it will. Isn't technology a beautiful thing?

Cons: If this is going to peddled to the DIY market - instructions need to be revamped.

Read Instructions Carefully!

Danny T. from Oklahoma City, OK on 1/24/2013

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

This Adapter does work as advertised, however, you have to read the instructions very carefully, and proceed slowly, re-checking the instructions as you begin to connect the multitude of wires together. If you don't have some prior automotive wiring experience, I would recommend you don't tackle this on your own. You will get frustrated quickly. I have plenty of electronics/wiring experience, and it still took me almost two hours to get this thing wired up and installed properly. Lay everything out on a table, don't do this in the front seat of your car. Consult the wiring diagram from your aftermarket stereo as it will help you locate the correct wires. I recommend using crimp connections instead of soldering. Plug everything in, test to make sure everything is working, then pull it back out and use plastic ties or tape to clean it up. Be aware, there are a lot of wires, plus the large plastic module case. It was difficult to stuff all this behind my unit into the dash. Everything worked, but took me three tries to get the factory chimes to finally be audible. I had to call Crutchfield for assistance with that part. But hey, got On Star, steering wheel controls, can use my factory Bose amps and speakers.

Pros: Allowed me to keep all my factory options such as On Star, Bose system, and steering wheel controls.

Cons: Very complicated installation. Instructions could have been written better. No diagrams/illustrations, just all text. Volume adjustment for factory chimes needs to be improved


Mark P. from Alameda, CA on 1/20/2013

Crutchfield Customer Review (What's this?)

This adapter has been very frustrating to say the least. Cannot get the door chimes to work on my 05' Chevy Suburban. After several phone calls it was deemed defective so it was replaced. The second module was installed and again had no door chimes. This time I contacted Metra's customer service and went through with them a series of steps before they told me to contact the seller and get it replaced as they felt it was defective. Crutchfield sent a third module. I installed this today and again, no door / warning chimes. I've verified my wire connections all three times. I am beyond frustrated. The strange thing about this is that when I reconnect the negative battery cable after installing the new modules, the chimes work for 30 seconds then stop and will not come back on. Not too impressed with this product. Application: 2005 Chevy Suburban Bose Premium Sound System On-star Steering Wheel Controls

Pros: Steering wheel controls work

Cons: Cannot get the chimes to work


TR H from ATL on 1/14/2013

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

Certain wiring instructions are verified incorrect and have been submitted to the mfg. Review directions for a current revision date, or contact Crutchfield for details. Application: 2003 GMC Sierra Denali, Bose Lux system.



Didn't work well in GMC Sierra with Bose

Geno from Colorado on 12/30/2012

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

I installed this on a GMC Sierra with the Bose system. It took a while but the instructions and help from both Crutchfield and Axxess was pretty good. I installed it and got everything working except the chimes, I would just get a low volume high pitched tone. Crutchfield replaced the unit and the second unit did the same thing (lots of soldering to do all this). The unit did work well if the chimes had so I only would give this a 2.

Pros: More automatic on setup than the Crux. The parking and reverse lights are all supported so that is much easier than other models. You can program the steering wheel controls where other models you can't.

Cons: Chimes did not work. Reprogramming the steering wheel controls are very confusing.


Bernard893 from Escondido, CA on 12/21/2012

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

This cost too much and is a pain. This comes with a harness for every possible vehicle but does it come with easy labeling for which harness is for what vehicle? NO. After trial and error I found the right harness once all the connections were made I tried to follow the badly translated instructions. Nothing worked like what the instructions said. I did finally get my steering wheel controls to work but after hours I trying for the door chimes they still don't work. They work if I reset the unit and I don't plug in the new head unit but as soon as you program GMOS-100 or plug in the new radio the chimes disappear never to found again. I guess I still need this hunk of junk until I replace the Bose system in my car but as soon as that is done this thing is getting run over with my car. I have installed many complicated car stereo components but this one was the worst and I'm even an electrical engineer and I still couldn't make head or tails of this.

Pros: It did retain the steering wheel controls after much trial and error.

Cons: It is a piece of junk. Not worth the the price even if it is half off of its normal price. Chimes don't work OnStar turns off radio instead of muting Bad translations Bad instructions

Crutchfield response on 1/29/2013 We forwarded this review to our Technical Support team for follow-up. Lifetime tech support comes with every Crutchfield purchase.

This worked perfect on my 2004 Silverado crewcab with Bose,XM,SWC and

Mike from San Antonio,Tx. on 12/2/2012

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

Was leery of this product after reading the reviews. It worked perfectly the first time! The main thing is READ THE DIRECTIONS A COUPLE TIMES before you start. Having some wiring experience will help greatly. Remember this adapter includes parts for more than one type of installation.

Pros: Worked exactly as advertised. Used with AVH-P3400BH

Cons: None yet.

There has to be a better way...

Murphydt5 from Florida Keys, FL on 12/1/2012

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

Well, you need only read through some other reviews to get the main points. Instructions are pathetic, there are way too many wires and harnesses you don't need or use included in the kit, the assembled unit makes fitting the radio into the dash almost impossible, and you better know what you are doing. The XM Radio DOES NOT transfer seamlessly over using this on a 2005 Suburban. While it does reetain the XM signal, you have to climb into the backseat and turn on the rear seat audio controls in order to see what you are listening to..which is dangerous at highway speeds. All the other stuff, OnStar, steering wheel controls, and door chimes do indeed work as they used to...small blessings.

Pros: It does most of what you are trying to do in retaining steering wheel function, door chimes and what not.

Cons: It is a pain to install, it includes a plethora of crap you don't need, and it does NOT retain full functionality of XM even with a head unit that has a screen for display.

Not a user friendly device for a DIY. seek professional help!

2010 sliverado LTZ w/bose (extended cab) from youngstown ohio on 11/11/2012

2010 Chevrolet Silverado
Crutchfield Customer Review (What's this?)

I bought for my 2010 sliverado ltz, ext cab w/bose. Was used with a kenwood dnx6990 which is a very nice head unit. The gmos100, this product will get the job done, but not without some bumps along the way. The professional I hired to install it said he had only installed 4 previously like this and had experienced multiple issues with each unit. He had to update the software twice to get the steering wheel controls to work. He also informed me that they usually will use individual interface components for each factory function they wish to retain. I wish I would have read these reviews before I bought, I would have searched for an alternative.

Pros: It does what it is supposed to do-- maintains steering wheel controls, door chimes, factory Bluetooth, factory sirus xm,

Cons: xm sirus now displays through odometer screen(very bad alternative to keep factory xm radio), I also have some motor noise that only occurs while listening to xm radio. I guys at Audio Extreme told me that they were not impressed with this unit at all. The spent several hours on the phone with tech support to get this to work correctly.

Not Impressed

plumber802 from Swanton,Vermont on 10/9/2012

I can't believe I paid even half price for this interface.My 2008 Silverado 2500 LTZ is equipped with BOSE audio and Onstar and I was told I needed this to retain all functionality.First of all the GMOS-100 comes with several harnesses that will accomodate many vehicles which caused much confusion.The instructions are vague at best.I read online that there was some confusion as to the direction you need to turn the gain adjustments on the unit for chime volume.I did call Crutchfield to confirm that clockwise was to turn up the volume.Well,come to find out that the opposite is true.I will need to dig into my dash yet again to adjust it to the proper volume.If you have limited space behind your head unit you will have trouble fitting the bulk of the box and the wiring back there.Also,any firmware update requires removing the GMOS-100 and connecting to a special cable within the unit itself.What a pain.If you can get by without this interface do yourself a favor and save some money.Not worth half price when purchased with a head unit and most certainly not worth full retail.Avoid this item if at all possible.

Pros: Integrates BOSE,Onstar and steering wheel controls.

Cons: Bulky,difficulty updating firmware,confusing gain controls,too many different harnesses included.

Straight forward, but....

Greg W from Columbus, OH on 10/8/2012

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

I ordered this unit for an install on a 2006 GMC Envoy. Ultimately everything works fine and the instructions were straight forward and easy to follow. All of my steering wheel controls work seamlessly. The OnStar system works just as it did before with the factory system too. The only problem that occured was that the harnesses came in mislabeled bags. Because of this I initially used the incorrect harness. This resulted in calling Tech Support (which was extremely helpful and knowledgeable) when the instructions referneced a harness connector that I didn't have. Finally, after talking to Tech Support and them sending me a picture of the harness I needed, it was smooth sailing. All and all, I am very satisfied with this product.

Pros: Works as described, retains all of the factory chimes, steering wheel controls, OnStar, etc. Straight forward to install if you follow the directions. The unit is smaller than I anticipated.

Cons: Harnesses can be mislabeled causing re-work. A few pictures in the instructions would go a long way.


Harward from Verona KY on 9/30/2012

Crutchfield Customer Review (What's this?)

I would not recommend this to anyone. This largish product will not actually fit behind anything in the stock radio compartment in a silverado truck except something, perhaps that has a very shallow depth. Installing it is enormously complicated and therefore problematic. FOr example, the box contains several harnesses. When reading the instructions, no where does it say you will not be using all the harnesses. Gets better, there are two identical looking harnesses, I mean identical. One is correct for your application, and one is not. Never guess which one I took some time to carefully solder into the radio leeds? Bingo. So, after you cut the incorrect harness out and place the first of many tech service calls to Crutchfield you suffer your first anxiety attack because there is a very real possibility that 1. You now own a piece of junk, 2. It may not actually work, 3. did you just screw up the wiring on your pricey new after market radio as well, 4. you crimpted or soldered into your factory harness, possibly screwing that up, 5. THere is also the real possibility now that nothing will work again, and did I mention, 6, Iw actually, physically DOES NOT FIT! I gave it two stars. Why two you ask. Well, after two days I removed lots of unecessary skin tissue off my knuckles and fingers trying to shove it in there somewhere, and that has to be OK, right? And secondly, and most importantly on the pistol range at 15 feet the large size of the thing makes a perfect target!

Pros: Makes a decent pistol target up to 15 feet

Cons: Well, this space has a limit of only 5000 words, so I couldn't even write the introduction for the book titled, "Just how awfully designed could something possibly be" So let me just say that you can't even grind it up int descent scrap.


05 Tahoe from pennsylvania on 7/31/2012

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

This part is very expensive. Soo many wire packages come with this kit with no explanation of where they go. The steps in the directions don"t give you the part number they are refering too. I had to call tech support. Which they were able to help me, but the step by step directions should be re-written to make it user friendly.

Pros: Simple to install once you call for directions.

Cons: Too expensive and the directions needs to be re-written.


Brad from Natchitoches, LA on 7/20/2012

Crutchfield Customer Review (What's this?)

Poor general design, it is designed to fit too many vehicles leaving you with many left over wires that must be bundled up and held out of the way. Not clear directions, hard to find room in the dash for the box. Works once installed, just like many new items, one size fits most, but not well on any.

Pros: Allowed me to keep all of my factory options, steering wheel controls, onstar, door chime, etc.

Cons: Poor directions, one size fits all which makes it difficult to install and hard to place in the dash, one roll of electrical tape later (to tape up all of the unused appendages) and it fit much better, but does not look as nice and professional as I like, but only I will see it. The should sell direct fit adapters even if they cost more. I will gladly pay more for quality.

GMOS 100 - Radio Wiring Experience Recommended

Joe from Detroit, MI on 7/19/2012

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

To put it briefly, this adapter does the job of keeping all the original factory functions in my 2006 Imapala with the Bose system. Once I wired and plugged everying together and tested the setup, it worked as advertised. However, there are some pretty glaring issues with this kit. First, they send you apapter harnesses for a large spectrum of GM vehicles, which means that you receive much more wiring and materials than you will actually use. I don't really understand why this is done. It would be pretty simple to separate the kit into more specific vehicle groups, saving significant costs and confusion. The instructions were pretty tough to follow, and did not specify a few necessary connections to be made. My experience with installing several previous radios came in very handy here. Finally, the fully assembled harness is massive, and could be very difficult to stuff in behind the radio during installation. It did get the job done, so I'm giving 3 stars.

Pros: Works as advertised. Factory chimes, onstar, steering wheel buttons, and XM all carry over. Expandable to allow addition of navigation, rear entertainment, and backup camera functions.

Cons: Possibly intimidating for an inexperienced installer. Very large harness to fit behind radio during install.


Anonymous from Anchorage AK on 7/13/2012

2007 GMC Sierra
Crutchfield Customer Review (What's this?)

I have a 2007 GMC Seria with the Bose system and I installed a Kenwood DNX7190HD using the GMOS-100. The instructions are pathetic! This adapter is made for experienced installers. The wiring harnesses and plugs aren't marked very well so it will take some time to figure it out. As far as operation goes, it works as advertised. All of my steering wheel controls were automatically recognized/retained along with my Onstar.

Pros: Retains steering wheel controls

Cons: The instructions are made for professional installers

Axxess GMOS-100 GM Factory Integration Adapter

Rmags from Rocky River,OH on 6/8/2012

2011 GMC Savana
Crutchfield Customer Review (What's this?)

This adapter is made to connect all the factory functions to the radio. It took six calls to tech support to get it right-the instructions weren't very clear and complete. Thanks to the Tech Support team!

Pros: Makes it all work!

Cons: A universal adapter that fits many models. You end up with extra parts, which during install adds to the confusion. The instructions are not complete, nor clear. The adjusting screw on the interface was reversed from the directions.

So far, So Good

Brad from Paulina, La. on 6/7/2012

2010 GMC Sierra
Crutchfield Customer Review (What's this?)

I installed this the other day and it seems to be working fine so far. It was not that difficult to install, just take your time and READ the directions. I did have one question and called Crutchfield and they were great as advertised in previous reviews.

Pros: Keeps factory setting and steering wheel controls.

Cons: A lot of unused wires.

Poor quality control

Anonymous from Chula Vista, CA on 4/30/2012

2011 Chevrolet Silverado 2500/3500
Crutchfield Customer Review (What's this?)

This product is expensive and does not work as advertised. First this is not Crutchfield issue but a manufacturer issue. Once I received the product I was missing one of the harnesses. but I was able to work around it since I was able to connect it to the speakers without using the connector adapter. The adjustment for the chimes did not work so unit had to be replaced. When I tried to insert the connectors the unit they did not insert, after investigating I noticed the covers was placed on incorrectly. When I opened the replacement unit it was missing a different harness good thing the first unit had that harness. I have most chimes working at this time with the exception of the turn signals. The adjustment for the chimes is a little touchy. I recommend looking for a different product. Please note this is not Crutchfield issue they have more than accommodating.

Pros: None

Cons: Does not perform as expected, poor QA.

Doesn't work on 2009 Saturn Aura

Dave from Howell, MI on 4/24/2012

2009 Saturn Aura
Crutchfield Customer Review (What's this?)

Purchased this with a new radio through Crutchfield. Connected all the wires. Didn't work. No ignition power to the radio with the key on. Checked and verified all the wires were connected correctly a half dozen times. Door chime worked and red LED flashed on the GMOS interface but no ignition power from the interface to my radio. Called tech support and they sent another one. Re-connected everything back up and same exact problem. Trying a 3rd time with a different interface. If this doesn't work, I'm done and everything is going back.

Pros: none at this time.

Cons: Doesn't work. Additionally, the manual has some errors so I question the accuracy for good installation. For example, there's a black/yellow wire that is mentioned but no description of what it is used for or where to hook it up. Also, the GMOS11 section I'm using the 20,22 & 30 pin connectors. At the end it says to plug in the 12 & 14 pin connectors to the interface. I'm not sure where that came from. I suspect someone cut & paste the instructions and didn't really review it.

A Decent Solution

Rick F from Southeastern PA on 4/19/2012

Crutchfield Customer Review (What's this?)

First off, there are alot of wires to connect and you must follow the wiring instructions to the letter. I would highly reccomend soldering and heat shrink tubing for your connections, as I did. Everything worked as advertised, right away. Then 24 hours later the steering wheel controls stopped working. Crutchfield was very helpful and ordered me a new unit. When it came I put it in and no luck, same problem. I called them back they sent me a new Kenwood head unit, problem solved. So I can't say it was the fault of the GMOS100, the HU or both. This unit is installed in a 2012 Chevy Traverse (GMLAN29) All the features work well, factory Bluetooth, Onstar, SWC, Chimes, Turn Signal clicker. Overall volume is good once it's tweaked by the pots on the module. SiriusXM control is very odd, you can only control it with the sterring wheel controls and it will only display on the dash cluster DIC, instead of the head unit. The skip track buttons on the SWC also change the SiriusXM channel, regardless of whether you want it to or not. This is not a great solution. Also the sound quality is not what you would expect from a digital satellite source. MP3 & ACC files played from a DVD or iPhone sound much better. FM source sounds better as well. I believe this is due to the crappy factory XM module. The instructions were difficult to understand due to the fact that there are 3 GM systems that this unit works with and the operational directions are all lumped under the GMLAN II section.

Pros: An all inclusive solution for GM vehicles. Overall quality is good.

Cons: SiriusXM operation leaves alot to be desired. Instructions could be better organized.

Axxess GMOS-100 GM Factory Integration Adapter

AndyA from Clarkesville TN on 4/14/2012

2009 Chevrolet HHR
Crutchfield Customer Review (What's this?)

I bought this unit so I could keep all my stock options including Onstar and my steering wheel controls. After seeing the mess of wires provided with the box I decided to take it to a professional installer who couldn't get it to work. They called Metra (the manufacturer) and after working through it with them, Metra said it was a known problem and recommended I exchange it for a new one. I'm not sure how well it actually works since I had the installer use another brand.

Pros: Can't say.

Cons: After it was on back order for two weeks, Metra is shipping them with known Quality Control issues?

Messy install

Nickmac14 from Southern Illinois on 3/15/2012

2008 Chevrolet Silverado
Crutchfield Customer Review (What's this?)

Big pain in the butt... about 100 feet of wires, half of which you dont use have to be shoved into a little tiny hole in your dash. Instructions are decent but what they dont tell you is that after you call Crutchfield support and have to wait for 19 other people that they know why your steering wheel controls dont work... its because the instructions dont tell you to connect the blue/white wires together, but Crutchfield knew about it, they just forget to mention that until you have everything already installed and shoved into your dash after 4 hours of soldering and reading instructions hoping that you wired it right so you dont have to do it again. Awesome, thanks guys!

Pros: Works like it should?

Cons: Instructions incomplete 500 extra wires 500 feet of wire Barely fits in a fullsize Silverado dash 125$-250$ for a 20$ plastic box/wires


Hands-on research

Product Research

Adapter Features
Class II Harness
GMLAN 11 Harness
GMLAN 29 Harness
Installation Notes

Adapter Features

Overview: The GMOS-100 is a GM all-in-one solution to add an aftermarket radio to select 2000-up GM vehicles with the CLASS II, GMLAN 11, or GMLAN 29 bit data systems. The GMOS-100 can be used to retain your factory amplifier, OnStar, Bluetooth, Satellite Radio (factory D.I.C. or optional LCD required), steering wheel controls, rear-seat entertainment (GMLAN 29 harness only; depending on type of vehicle), and factory backup camera (GMLAN 29 harness only; depending on type of vehicle). In addition, all the warning chimes and convenience features are retained that are normally lost when the OEM radio is removed. The GMOS-100 also provides a 12-volt/10-amp accessory output and connections to help install a navigation radio which include VSS, Parking Brake, and Reverse (rear-view camera).

Note: There are three types of GM harness included (CLASS II, GMLAN 11 bit, and GMLAN 29 bit). Only one will be used for your specific vehicle. Please consult Crutchfield's Outfit My Car to see if your vehicle is compatible and what additional accessories will be needed.

Class II Harness

Class II Harness Compatibility Chart: The included Class II harness is compatible with the following 2000-up Buick, Cadillac, Chevrolet, GMC, Hummer, Isuzu, Oldsmobile, Pontiac, Saab, and Saturn vehicles (as of October 2012):

Make Model Year
Buick Allure 2005-2009
Century 2004-2005
Lacrosse 2005-2009
Rainier 2004-2007
Rendezvous 2002-2007
Terraza 2005-2008
Escalade 2003-2006
Escalade EXT 2003-2006
Chevrolet Avalanche 2003-2006
Cavalier 2000-2005
Corvette 2005-up
Express 2003-2007
Impala 2000-2005
Malibu Classic 2004
Monte Carlo 2000-2005
Silverado 2003-2006
Silverado Classic 2007
SSR 2003-2006
Suburban 2003-2006
Tahoe 2003-2006
Trailblazer 2002-2009
Uplander 2005-2008
Envoy 2002-2009
Savanna 2003-2007
Sierra 2003-2006
Sierra Classic 2007
Yukon/XL/Denali 2003-2006
Hummer H2 2003-2007
H3 2006-2009
Isuzu Ascender 2003-2008
I Series 2006-2008
Oldsmobile Alero 2001-2004
Bravada 2002-2004
Intrigue 2002
Silhouette 2000-2004
Pontiac Aztec 2001-2005
Grand Am 2001-2005
Grand Prix 2004-2008
Sunfire 2000-2005
Saab 9-7x 2005-2009
Relay 2005-2007

Class II Harness Feature Set:

  • 10-Amp ACC 12v output
  • Retains all factory warning chimes
  • Retains OnStar *
  • Retains factory amp *
  • Retains Steering Wheel Controls *
  • Retains factory Bluetooth *
  • Retains factory Satellite Radio (RCA AUX input and separate XIA-LCD required)
  • Provides Navigation outputs (VSS, Park Brake, Reverse signal)
Note: *If equipped

GMLAN 11 Harness

GMLAN 11 Harness Compatibility Chart: The included GMLAN II harness is compatible with the following Chevrolet, Pontiac, and Saturn vehicles (as of October 2012):

Make Model Year
Chevrolet Cobalt 2007-2010
HHR 2006-2011
Malibu 2008-2012
Pontiac G5 2007-2009
G6 2009-2010
Solstice 2006-2009
Saturn Aura 2007-2009
Sky 2007-2009

GM 11-Bit LAN Harness Feature Set:

  • 10-Amp ACC 12v output
  • Retains all factory warning chimes
  • Retains turn signal indicators via pre-wired relay
  • Retains OnStar *
  • Retains factory amp *
  • Retains Steering Wheel Controls *
  • Retains factory Bluetooth *
  • Retains factory Satellite Radio (RCA AUX input and separate XIA-LCD required)
  • Provides Navigation outputs (VSS, Park Brake, Reverse signal)
Note: *If equipped

GMLAN 29 Harness

GMLAN 29 Harness Compatibility Chart: The included GMLAN 29 harness is compatible with the following 2006-up Buick, Cadillac, Chevrolet, GMC, Hummer, Pontiac, Saturn, and Suzuki vehicles (as of October 2012):

Make Model Year
Enclave 2008-up
Lucerne 2006-2011
Cadillac SRX 2007-2009
Escalade 2007-up
DTS 2006-2011
Chevrolet Avalanche 2007-up
Equinox 2007-2009
Express 2008-up
Impala 2006-up
Monte Carlo 2006-2007
Silverado (new body) 2007-up
Suburban 2007-up
Tahoe 2007-up
Traverse 2009-up
GMC Acadia 2007-up
Savanna 2008-up
Sierra (new body) 2007-up
Yukon 2007-up
Hummer H2 2003-2009
Torrent 2007-2009
Outlook 2007-2009
Vue 2008-2009
Suzuki XL-7 2007-2009

GM 29-Bit LAN Harness Feature Set:

  • 10-Amp ACC 12v output
  • Retains all factory warning chimes
  • Retains turn signal indicators via pre-wired relay
  • Retains factory backup cam (video unit with rear cam RCA input required)
  • Retains Rear Seat Entertainment (rear-panel RCA AUX input required)
  • Retains OnStar *
  • Retains factory amp *
  • Retains Steering Wheel Controls *
  • Retains factory Bluetooth *
  • Retains factory Satellite Radio (RCA AUX input required, D.I.C. and factory SWC required, otherwise XIA-LCD must be used)
  • Provides Navigation outputs (VSS, Park Brake, Reverse signal)
Note: *If equipped

Installation Notes

Satellite Radio Note: Your factory Satellite Radio information will continue to be displayed through your vehicle's factory Driver Information Center (D.I.C.). This factory D.I.C. is not removed when replacing your factory radio with your new aftermarket head unit. If your vehicle is not equipped with a separate Driver Information Center and the factory radio displays all Satellite Radio information, you will lose Satellite Radio text, unless you purchase the XIA-LCD (120XIALCD, sold separately), which provides a separate LCD screen from your new aftermarket stereo and allows you to navigate through factory installed Satellite Radio options.

Note: Vehicles that require the GMLAN29 harness still allow you to control your factory Satellite Radio through your vehicle's factory steering wheel controls, even without the Driver Information Center; but you will lose text display.

OEM Steering Wheel Control Compatible: The GMOS-100 features a 3.5mm connector that lets you keep your GM vehicle's OEM steering wheel controls when installing a compatible aftermarket radio.

Level Adjustments: The GMOS-100 provides chime/turn signal volume adjustment, overall gain level adjustment, and OnStar level adjustment.

  • Chime/Turn Signal Volume Adjustment: To adjust the chime volume, use a small screwdriver to rotate the module's potentiometer (located on the 8-pin harness side of the interface; closest to 8-pin harness). Turn clockwise to make the chime/turn signal louder and counterclockwise to make the chime/turn signal softer. Turn signal will not be affected in non-amplified or class II systems.
  • Overall Gain Level Adjustment: To adjust the overall audio volume of your vehicle, use a small screwdriver to rotate the potentiometer, located on the 8-pin harness side; furthest away from 8-pin harness). Turn clockwise to make gain louder and counterclockwise to make the gain softer.
  • OnStar Level Adjustment: To adjust the OnStar volume level, find the Black/Yellow wire on the 20-pin harness. Push the blue OnStar button, while the voice is speaking tap the Black/Yellow wire to ground. There are 4 volume settings for OnStar; once the 4th setting is reached and the Black/Yellow wire is tapped to ground it will automatically go back to the first volume setting. Once the volume is set, it will stay at that volume until the Black/Yellow wire is tapped to ground again. This can be set during installation and then left alone. If user adjustment is desired, a momentary contact switch (sold separately) can be added. Connect one terminal from the switch to ground and the other terminal to the Black/Yellow wire. The volume will change one level every time the switch is pressed.

RSE/Backup Camera Note: The GMOS-100 only retains factory RSE (rear seat entertainment) and backup camera in select vehicle's which require the GMLAN29.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.