Skip Navigation

Metra GMOS-09 Factory Integration Adapter

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

Item #: 120GMOS09

Be the first to write a review

This item is no longer available.

Original Price: $149.99

Shop all Factory System Adapters

Does it fit my car?

Select your car

Find what fits your car

Can't find your exact car?

Metra's GMOS-09 GM radio replacement adapter lets you replace the factory radio in select OnStar-equipped 2000-05 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.

Hook the GMOS-09 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-09 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 2000-05 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: 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.

Metra GMOS-09 Factory Integration Adapter Reviews

Hands-on research

What's in the box?

Download owner's manual

  • GM/OnStar Class II data bus interface (GMOS-09)
  • 10-Pin harness with RCA's
  • 16-Pin to 32-Pin harness
  • Installation Instructions

Product Research


Overview: The AXXESS GMOS-09 interface is designed to allow you to replace the OEM radio with an aftermarket headunit in factory-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-09 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.

Note: Your aftermarket radio must have two pairs of preamp outputs in order to properly interface with the GMOS-09. If it doesn't you will need to connect the receiver to a line output converter (such as item # 142SLC4, sold separately). The GMOS-09 will accept a preamp signal of up to 4 Volts.

Navigation Compatible: The GMOS-09 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-09 is compatible with the select 2000-2005 GM vehicles (with or without Onstar) that use the "Dock-n-Lock style harness". 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-09 is designed to retain this feature.

OEM Steering Wheel Control Compatible (optional): The GMOS-09 features a 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).

Note: The GM vehicle must have factory steering wheel controls to retain access to the factory customization menu, once the factory radio is replaced with an aftermarket head unit.

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.