Skip Navigation

Axxess GMOS-05 Wiring Interface

Connect a new car stereo and retain OnStar®, RAP, and the safety warning chimes in select 2000-05 GM vehicles

Item #: 120GMOS05

In Stock

4 Reviews | Ask Questions

Your price: $79.99 Earn up to 80 Rewards points

Add to Cart

+ Add to wishlist + Email me alerts for this product

View all associated offers

Does it fit my car?

Select your car

Find what fits your car

Can't find your exact car?

Metra's GMOS-05 radio replacement interface lets you replace the factory radio in your Onstar-equipped 2005 Buick LeSabre or 2005 Pontiac Bonneville using the existing wiring and connectors. Even if you don't subscribe to OnStar, you'll need this adapter to connect an aftermarket stereo.

Hook the GMOS-05 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. The GMOS-05 also includes the connection you need if you plan to install an aftermarket navigation receiver.

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 2005 Buick LeSabre and Pontiac Bonneville 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: 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.

Axxess GMOS-05 Wiring Interface Reviews

Average Customer Review:

4 Reviews

Works great!

Written by: Ray from Fort Wayne ,IN on February 2, 2016

Crutchfield Customer Review (What's this?)

Only 4 stars because Crutchfield were out of them when I ordered. Waited some extra days but we'll worth it.

Pros: Fits my 2005 Bonneville

Cons: Nothing.

Perfect wiring accessory for stereo installation

Written by: DanG from Montana on January 4, 2016

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

Instructions were clear and easy to understand & follow. Everything worked as it was supposed to. I highly recommend this.

Pros: Everything is included, wires are labeled along edge of wire, very handy if your color blind like me.

Cons: Wires are very small gauge and delicate to work with.

Great Product

Written by: Anonymous from Philipsburg, PA on July 5, 2014

This is exactly what I needed to install an aftermarket head unit in my 2005 Buick Le Sabre. It keeps the door chimes perfectly and the unit powers off when the doors open. It takes a bit of cutting and modifying to fit everything in the dash though.

Pros: Detailed Instructions, works perfectly.

Cons: Lots of wires, need to cut into dash to make aftermarket head unit and adapter fit. All unavoidable.

Necessary extra

Written by: AndrewL from Saint Paul, MN on September 5, 2013

2005 Buick LeSabre
Crutchfield Customer Review (What's this?)

This is necessary to retain door chimes and OnStar. I don't use nor will I use OnStar and you might think it's unnecessary to buy a 65 - 120 dollar part for door chimes but they are more useful than you think.

Pros: Retains Door Chimes and OnStar

Cons: More to fit in a small space. Unavoidable.

Hands-on research

What's in the box?

Download owner's manual

  • GM/OnStar Class II data bus interface (GMOS-05)
  • 14-Pin harness
  • 12-Pin to 32-Pin harness
  • Installation Instructions

Product Research


Overview: The AXXESS GMOS-05 interface is designed to allow you to replace the OEM radio with an aftermarket headunit in non-amplified GM vehicles equipped with the "Dock-n-Lock" style harness and retain full functionality of the Onstar system as well as all safety and warning chimes. The GMOS-05 will also retain the retained accessory power convenience features (R.A.P). This interface has the capability of adjusting chime and Onstar volumes as well.

Navigation Compatible: The GMOS-05 also provides Mute, Parking Brake, VSS or Speed Sense, and a Reverse Output to make installing an aftermarket Navigation radio simpler and less time consuming.

Vehicle Compatibility: The AXXESS GMOS-05 is compatible with the following 2000-2005 GM vehicles (with Onstar) that use the "Dock-n-Lock style harness".

  • 2000-2005 Buick Lesabre
  • 2001-2002 Oldsmobile Aurora
  • 2000-2005 Pontiac Bonneville
Note: This interface will also work in vehicle listed above that are not equipped with Onstar. This interface will not work to retain factory amplifiers. Please consult the Crutchfield Car Selector to see if your vehicle is compatible.

Retained Accessory Power (R.A.P.): The ignition power source of most GM vehicles keeps the radio on until one of the doors is opened. This feature is called the R.A.P. (retained accessory power). The GMOS-05 is designed to retain this feature.

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.

Customer Q&A

Searches related to the Axxess GMOS-05 Wiring Interface Connect a new car stereo and retain OnStar®, RAP, and the safety warning chimes in select 2000-05 GM vehicles