Name: Metra GMOS-01 Wiring Interface
Brand: Metra
SKU: 120GMOS01
Price: 79.99 USD
Availability: InStock
Rating: 4 (183 reviews)

OVERVIEW

by Crutchfield's

Metra's GMOS-01 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 interface to connect an aftermarket stereo.

KEEP READING

Hook the GMOS-01 to your aftermarket radio, mount the module, and plug it into the existing factory plug. Get the great sound you want, and keep all important safety features intact. And you can adjust volume settings for OnStar as well as the safety chimes. Also, once you turn off the ignition in these GM vehicles, the 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-up GM vehicles. 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 this item is compatible with your vehicle. Warranty: 1 year.

Note: The GMOS-01 will not work with factory-installed Bose car audio systems.

READ LESS

What's in the box:

Metra GMOS-01 Wiring Interface owner's manual

GMOS-01 Class II Data Bus interface
Wiring harness with 10-pin Molex on one end and bare wires on the other
Wiring Harness with 12-pin Molex on one end and 24-pin Molex and 12-pin Molex on the other (plus bare wires)
Installation instructions

MFR #GMOS-01

REVIEWS

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DETAILS

Researched by Crutchfield's Stacey B.

Product Research

Features

Overview: The GMOS-01 lets you install an aftermarket receiver in select late model GM vehicles without losing the OnStar Emergency Services features or the chime that warns the door is open. Please check the Crutchfield Vehicle Selector to confirm compatibility with your vehicle.

Note: This adapter is not compatible with factory Bose or Monsoon systems.

Connections: The module includes a 10-pin harness (5 pins used) that connects to the switched power and front speaker leads of the new radio. A second harness (12-pin, 10 used) connects the module to the factory OnStar and radio plugs, plus the rest of the wiring for the new radio.

OEM Steering Wheel Control Compatible (optional): The GMOS-01 features a right-angle 3.5mm connector that lets you keep your GM vehicle's OEM steering wheel controls via the optional Axxess Steering Wheel Control Interface (120ASWC1, sold separately).

Volume: The volume is adjustable for both the OnStar output and the warning chime.

ACCESSORIES

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Q&A

Q

Crutchfield asked: Why did you buy this?

because it was needed for install [ DOUG May 14, 2020 ]

Installing after market radio [ George May 10, 2020 ]

because i am told that it will use the existing OnStAR mic for bluetooth function, and I won't have to install a separate mic [ Jeremy May 02, 2020 ]

Will fill my dash perfectly [ Daniel Jan 06, 2020 ]

Make the wiring process quick and easy. [ Rodney Nov 04, 2019 ]

I failed to identify my 2012 Chevy Colorado has door tweeters so I needed to order the correct harness. I also forgot to order a Sirius XM tuner. No worries. I'm an old burnout! You guys have rocked every vehicle I've owned since you've existed! Thanks for everything you do! [ Jeffrey Sep 15, 2019 ]

There wasn't any other option to retain OnStar and it's overpriced because of that reason. [ Anthony Jun 24, 2019 ]

Exact match with my car/options [ ALAN Apr 15, 2019 ]

It was recommended [ Rory Feb 24, 2019 ]

needed for vehicle [ Dan Feb 08, 2019 ]

to make installation easier [ Daniel Jan 30, 2019 ]

I need it for my radio. [ LEON Oct 25, 2018 ]

Needed a wiring adapter [ Joseph Sep 24, 2018 ]

needed [ Dale Jun 24, 2018 ]

For car instalation, i need [ jose Jun 03, 2018 ]

There's really only one or two ways to install a radio. the right way and then any other way. [ Clifton Apr 23, 2018 ]

Because your engineers said i need it to insure door chimes, light chimes, OnStar continue to work. [ Charles Apr 09, 2018 ]

To keep factory/ on star [ kyle Mar 15, 2018 ]

One of the better RAP harness for GM vehicles. Retaining the factory alert chimes is important to me. [ Ollie Feb 28, 2018 ]

Because it's the best bang for the buck. GM is awesome, but having to buy this extra expensive harness sucks... [ Joshua Jan 07, 2018 ]

because crutchfield recommended it for the installation [ Jared D. Oct 28, 2017 ]

Recommended by a number of online posts [ Bruce Jun 27, 2017 ]

Jenny ,my advisor, recommended this [ Benji Apr 21, 2017 ]

Advisor stated it should work with my Chevy Kodiac C5500. [ Stosh Apr 03, 2017 ]

Recommended accessory to keep the OnStar, chimes, etc working on the car after I install the new head unit. I have one of these GMOS-01's for my current pioneer head unit that I am upgrading but want to make sure I can install it all so ordered a new one with this head unit. It's been in my car for about 10 years so figure I'd get a new one since it is discounted while purchasing the new unit. [ Thomas N Mar 22, 2017 ]

needed to install radio [ DAVID Feb 23, 2017 ]

other one doesnt work anymore and out of warranty [ dave Feb 20, 2017 ]

Recommended by service tech [ Micky Dec 17, 2016 ]

needed it [ george Nov 29, 2016 ]

I chose this item because it signals my car aftermarket radio to turn on. my car did not have an ignition switched wire only 12v constant so I needed something to provide it with one. this item seems to do the trick. [ CAMERON Aug 14, 2016 ]

Fits my colorado [ phillip Aug 14, 2016 ]

Very easy to hook into existing wiring and keep all the safety chimes. [ CHRISTOPHER Aug 11, 2016 ]

wanted to keep oem onstar [ Hans Aug 10, 2016 ]

Needed for install [ Rick Aug 08, 2016 ]

As much as I would like to eliminate that dinging when I leave my car door open, it reminds me to take my keys .... [ Dennis Jul 26, 2016 ]

The Metra interface aloud me to retain my trucks features [ Lyndale Jul 09, 2016 ]

retain OnStar service ! [ M Jun 13, 2016 ]

told me to [ Blake Jun 09, 2016 ]

I always look to Crutchfield...They are the easiest and most complete. Plus they are always only a phone call away for help! [ David Jun 08, 2016 ]

suggested for new unit installation [ Gerald May 20, 2016 ]

It was the right part for my application. Happy with purchase! [ Bobby Mar 24, 2016 ]

well, it was not due to the price,, but, when you have to have it you just need to get the best [ eric Mar 20, 2016 ]

A true must have to make for not only an easy install but to retain all your factory equipment. A must have for a professional install at home. [ David Feb 28, 2016 ]

To ensure factory chime, warning s and on-star still function while I'm getting my jam on. [ Big Joe Feb 12, 2016 ]

so I can install my radio and drive my vehicle [ Daniel Jan 31, 2016 ]

Came free with purchase of speakers [ Troy Jan 17, 2016 ]

required to install [ Thomas Dec 04, 2015 ]

SHOW MORESHOW LESS

11 questions already asked

After installing this, onstar audio only appears to be coming from the front left speaker. Is that expected? Other functionality of head unit is fine.

[ Petey Aug 22, 2019 ]

1 answer

Onstar and other vehicle sounds (door open chime, etc) only comes through the drivers side speaker even on OEM installations. This is normal.

[ William Aug 22, 2019 ]

Will this fit a double dinPioneer AVH-W4400NEX?

[ Avont Feb 03, 2019 ]

1 answer

The Metra GMOS-01 is a wiring interface for compatible vehicles. It will work with most aftermarket stereo models; regardless of their chassis size (single or double DIN). For additional assistance and personalized recommendations, feel free to contact us directly by phone or through our online chat service: https://www.crutchfield.com/support/ContactUs.aspx

[ Ryan Feb 06, 2019 ] Staff

want to put a new radio in my 2007 H3 Hummer . Will I need this?

[ Calvin Dec 18, 2018 ]

2 answers

If your vehicle is equipped with onstar yes, you will need this to retain all the features

[ Brandon Dec 18, 2018 ]

Yes definitly

[ Arnold Dec 18, 2018 ]

I have an '04 GMC Envoy, what is the 3.5mm plug used for? Can I plug it into the microphone port on my aftermarket radio and use the onstar microphone instead?

[ Brad Jul 25, 2017 ]

1 answer

You will want to contact an Advisor by phone (1-800-324-9695) or online chat to discuss compatibility with your factory system. They will be able to pull up your vehicle and see if this will integrate. If it does not, then they will also be able to discuss other options with you and determine what you will need for installation.

[ Kenny Aug 01, 2017 ] Staff

Will this product allow me to install an aftermarket stereo to my 2011 Chevy Colorado Z71 with Onstar (no Bose) and keep Onstar, door chimes, and all other stock functions that are run through the stock harness?

[ Stephen Sep 26, 2016 ]

1 answer

[ Krissy Sep 27, 2016 ] Staff

Will this harness retain my hands free phone option?

[ Gary Jul 22, 2016 ]

1 answer

[ Kenny Jul 22, 2016 ] Staff

this part Metra GMOS-01 will fit my 2003 GMC sierra 1500 SLT , i replace the factory cd to after maket cd-dvd-navigation will control by OEM steering wheel.So this part will do that?

[ khanh Apr 29, 2016 ]

1 answer

You can check to see if this will fit your vehicle by using our Outfit My Car tool: http://www.crutchfield.com/car/carselector.aspx For additional details on fit or installation please contact an Advisor by phone (1-800-324-9695) or online chat. They will be able to pull up your vehicle and give you the details on if this will fit and what you will need for an installation in your vehicle.

[ Kenny Apr 29, 2016 ] Staff

Is this compatible with a 2008 Gmc Envoy Denali? I have the Metra 71-2003-1 male harness. I want to replace the radio but I can't find a harness to match.

[ SimSim Mar 29, 2016 ]

1 answer

[ Krissy Mar 29, 2016 ] Staff

I have a 2001 Chevy Impala LS with OnStar, How do I keep the ability to change my vehicle customization settings, like oil reset, low tire pressure, set remote audible and light verification settings after I install after market radio? Will this harness allow me to keep making changes or reset tire pressure and oil life indications?

[ Xkiddrick Jan 01, 2016 ]

1 answer

[ Kenny Jan 01, 2016 ] Staff

radio not dimming with dash control dimmer GMOS 01 AVIC 6000NEX 2006 Envoy?

[ D Apr 18, 2015 ]

1 answer

If you purchased the product from Crutchfield, feel free to contact our Tech Support team. They can walk you through the settings on the product and see if there may be a fix. Our toll-free Tech Support number is printed on your invoice, and is also available under the "My Orders" tab in the "My Account" section of our website. If you did not purchase the unit from Crutchfield, then you may want to contact the manufacturer. You can also post your question in our forums: http://community.crutchfield.com. Or try our online support center: http://crutchfield.custhelp.com/app/answers/list/kw/.

[ Krissy Apr 18, 2015 ] Staff

If I am adding a new head unit, one amplifier for a newly-added subwoofer, and one amplifier to power the existing door speakers, is there any need in adding this module? I'm not sure that I quite see how this module would connect to the speakers if I am using an amp to power the speakers.

[ MikeMill Dec 28, 2013 ]

5 answers

Though late in the game this is what I have learned and hope it benefits everyone. The module can be used with amps, BUT you must bypass the module of the amp power and get an additional speaker for the warning chimes (Metra SP-2003 sadly not found at Crutchfield). On my 2004 Chevy Colorado I tried using one of the tweeters that I removed (when I upgraded to components) for the chime but it was too quiet whether it was wired before or after the inline resistor. Metra has specific instructions for using this module with amps on page 7 of the owners manual. I do NOT have OnStar so have no idea how this would play in, but if you want your warning chimes on a NON-OnStar vehicle then it appears getting the Metra SP-2003 (or possibly any 12V speaker with a good volume level) appears to be the only route to take when using amps and the Metra GMOS-01. I plan on ordering the SP-2003 in the near future but for now this is the best I have to offer. I do not pretend to know everything, or anything, but this is what my research has come up with and hope it helps any one looking for the same answers I had about the "amp" situation.

[ CycoStu May 28, 2014 ]

Hi, I didn't added an amp to my car, but I'm using the module, I have a 2005 buick lacrosse equipped with on-star. This module helps you keep the door chimes sound for door opens, or seat bealt alerts. Also keeps a Connction going from the radio to the rear view visor that has the built-in Mic in order to talk to the on-star assistant. The radio I bought with this module has its own Mic which I use for phone calls using the Bluetooth service. Hope this information helps.

[ RANSES A Dec 31, 2013 ]

Hi Mike, This unit doesn't have line level inputs or outputs. Provided the unit can handle the additional power of the amplifier, you could hook it up post amp. The purpose of this unit is to allow the OnStar system to use your speakers for communications. If you are wiring head unit-amp-speaker and bypassing the factory wiring and you are not worried with your OnStar the you really don't need it. Hope this helps Will MECP certified installer

[ WILLIAM Dec 29, 2013 ]

Mike M, I installed this in a GMC Envoy XL using just the standard speakers. I believe the adapter was required for maintaining the OnStar capabilities thru the new head unit. Unfortunately I didn't add additional amplifiers like you are but I believe the wiring would still be similar to the diagrams provided. I probably didn't give you much help with my answer but I think you should try to keep the adapter in the setup. I wired and soldered everything before hand before I even went out to the car so everything plugged in nicely once I got started. Good luck!

[ C S Dec 28, 2013 ]

The wiring harness makes this much easier to splice into the factory system - I suppose you CAN do it without but you'll have a lot more heartache and virtually no complications this way. This helps you retain OnStar and the door chime which will both disappear if you do not use this. There is also a PAC unit for GM cars that also works but you do not retain OnStar or the chime - which is the route I went. I have a Hummer H3 and this was necessary as the car had an external amp for the separates and no subwoofer. I added a sub (JL Audio Stealthbox) and new amp to replace the factory amp and a whole new amp for the sub.

[ ERIC T Dec 28, 2013 ]

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Metra GMOS-01 Wiring Interface

Connect a new car stereo and retain OnStar®, factory door chimes, and audible safety warnings in select GM vehicles

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