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Metra GMOS-06 Wiring Interface

Connect a new car stereo and retain OnStar®, RAP, and safety warning chimes in select 1996-05 Cadillac models

Item # 120GMOS06

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Item # 120GMOS06

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About the Metra GMOS-06 Wiring Interface

Metra's GMOS-06 wiring interface lets you replace the factory radio in select 1996-05 Cadillac vehicles with premium or Bose® audio systems, while retaining use of OnStar, all factory warning chimes, and audible turn signal indicators. Even if you don't subscribe to OnStar, you'll need this interface to connect an aftermarket stereo. The interface includes navigation outputs, so you can install an in-dash navigation receiver. Warranty: 1 year.

What's in the box:

  • GMOS-06 Cadillac OnStar Class II Data Bus interface
  • Wiring harness with 2" wide 32-pin blue plug on one end and a 1-3/8" wide 16-pin white plug on the other end
  • LD-NAVAMP harness with 1-1/4" wide (14-pin) plug on one end and speaker wire on the other end
  • Installation instructions

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More details on the Metra GMOS-06 Wiring Interface

Stacey B.

Product Research


Overview: The Metra/Axxess GMOS-06 is designed to interface an aftermarket stereo with the factory amplified audio system (including Bose) in select Cadillac vehicles with OnStar. It will retain the warning chimes that are lost when the factory radio is removed. The interface also provides a 12-volt switched accessory output, along with Mute, Parking Brake, Speed Sense (VSS) and Reverse outputs to allow you to install an aftermarket radio with navigation.

Compatibility: The GMOS-06 is compatible with the following Cadillac vehicles:

  • 1999-2005 Deville
  • 1999-2002 Eldorado
  • 1999-2004 Seville
  • 1997-2001 Catera (navigation outputs not available)

Level Adjustments: During the installation process, you can set the volume level of the OnStar voice commands. If the aftermarket radio has a high pre-out voltage, the audio signal may become distorted. The interface has a potentiometer that allows you to adjust the input level going to the factory amplifier. This potentiometer also adjusts the chime volume at the same time.

Retained Accessory Power (R.A.P.): The ignition power source of the Cadillac keeps the radio on until one of the doors is opened. This feature is called the R.A.P. (retained accessory power). The GMOS-06 is designed to retain this feature.

OEM Steering Wheel Control Compatible (optional): The GMOS-06 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.

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Customer Q&A

1 question already asked

Will this adapter make all the warning lights on my dash go off and make my gas hand start back working?
[ Anthony  Apr 09, 2014 ]
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.
[ Krissy  Apr 10, 2014 ]  Staff

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