Scosche CGM02 Wiring Interface

Allows you to connect a new car stereo and retain the factory amp in select 1986-up GM vehicles

Item #: 142C4GM02

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9 Reviews

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The Scosche CGM02 wiring interface allows you to integrate a high-powered aftermarket receiver into select 1986-up General Motors vehicles with premium factory systems. The package includes the OEA-4 adapter and a GM-specific harness. The OEA-4 unit has output-level gain controls for each of its four channels which can be adjusted to properly match the new receiver to the factory amplifier.

Note: If you haven't already, please enter your vehicle information or call a Sales Advisor at 1-888-955-6000 to find out if this adapter is compatible with your vehicle.

  • 4 speaker-level inputs
  • output level adjustments for all four channels
  • works best with high-powered aftermarket receivers
  • dimensions: 3-15/16"W x 15/16"H x 2-1/16"D
  • 1-year warranty

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.

Scosche CGM02 Wiring Interface Reviews

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Great harness

Written By William, Alger, Mi on Sunday, September 13, 2015

Crutchfield Customer Review (What's this?)

This harness works great. You need to hook the blue wire marked power antenna to the blue wire on your head unit. That powers the bose amp, otherwise you will have no sound.

Pros: Quick and clean hookup

Cons: Explain the blue wire to fire the bose amp.

Never disappointed

Written By Breff, Minneapolis, MN on Sunday, November 30, 2014

Crutchfield Customer Review (What's this?)

Everything fit like a glove and wiring kit makes it so easy.

Pros: Always great service ad products

Scosche CGM02 Wiring Interface

Written By Al, Farmville, NC on Saturday, July 12, 2014

Crutchfield Customer Review (What's this?)

Easy and worked perfectly.

Scosche GM adapter

Written By Jack, Palos Verdes,CA on Wednesday, March 26, 2014

Crutchfield Customer Review (What's this?)

A perfect fitting adapter.

Pros: Does the job without a problem

Cons: none

Scosche CGM02 Wiring Interface

Written By BobT, Carrollton, GA on Thursday, December 20, 2012

The Delco Bose in my '94 Camaro was always awful, and I jumped at the chance to replace it without having to change the speakers. I knew the adapter was not harness to harness and it was a pain to attach all the wires. The system sounded great after I realized that the blue wire was needed. The self powered speakers actually are an exterior amp, so I had to pull the unit from the dash and attach the amp wire (my fault.) After a couple of weeks of amazing sound the rear speaker quit. It's one speaker, with left and right wires attached, along with the grounds. I pulled the head unit again and found that when I touched the crimped connectors on the adapter, the rear speaker came on. I squeezed all the crimps for their entire length and got no more faults when wiggling the wires. I replaced the head unit and was fine until the next morning; the rear was dead again. Pulled the head unit and noticed that when I wiggled the rear speaker wires on the adapter itself I got intermittent sound. I then discovered that if I turned the adjustment screws on the adapter fully clockwise for the rear, I got some sound from the rear. I had to turn the adjustment screws for the front fully counter-clockwise to be able to turn the volume up enough to hear the rear speaker at normal volume. I buttoned it up and was pleased that I had finally figured it out. It again sounded great but only until the next morning. It sounds fine with just front speakers, I'm thru!

UPDATE: 12/31/12 I previously suspected this adapter was causing intermittent problems, but have traced my problem to a bad rear amp/speaker assembly. The front speakers are fine by themselves until I can get another rear unit; I do not want to replace the original speakers because it requires all new wiring. Bless the Scosche kit for avoiding that.

A tip for '94 style Camaro's. Plug the new wiring harness into the original plug and route the wiring to the side and then down in the pocket below the radio. Plug in the unit when you see a clear path to slide it in. The Scosche and all that wiring take up a lot of space.

Pros: Lets you use your Bose speaker(s).

Cons: Difficult to wire, maddening to to troubleshoot.

GM Factory System Integration Adapter

Written By John C., Melbourne, Fl on Friday, May 18, 2012

Crutchfield Customer Review (What's this?)

Worked in my 1991 Chevy Caprice. It is awesome! My audio never sounded so good and I got to use my Bose speakers.

Pros: Save a couple of bucks taking advantage of existing sound components, less work, not removing everything and rewiring.

Cons: Adjusting the gain with your dash partially disassembled, but not really a huge issue. It's not like you have wires all around hanging.

Vette Bose Replacement made easy

Written By Eric, Tampa Bay on Sunday, February 08, 2009

Crutchfield Customer Review (What's this?)

Absolutely great product. Made the install on the Alpine IDA-X300 quite easy. One thing to take note, make sure to make the harness about 4' longer. The harness you need to plug it into is under the rear storage compartment on C4 corvettes. So make sure to get 100' of 18 gauge wire, you'll have about 18 wires you'll need to add 4' to. I also recommend removing the passenger seat to make it easier to route the harness to the rear storage compartment. You can also remove the old radio control unit and the foam to add more storage room for any roadside assistant equipment you may carry (I now house a mini-air compressor, tire plug kit, tools, and a flash light UNDER the storage tray).

Oh, and the bose speakers have never sounded so good. I lost a tad bit of bass, but very very little. I may just need to do some more adjustments to the sound levels. Good luck and you won't be happier if you want to keep your stock speakers.

OEM Amplifier Intergration V.4

Written By Thomas, Honolulu, Hawaii on Sunday, March 02, 2008

Crutchfield Customer Review (What's this?)

This is the best product out there. I have a 1995 Corvette with the Bose sound system. All I had to do is install the Player Head. and make a wire harness with the alpine wire connector and the OEM amplifier Intergration V.4 Wire connector. Because The corvette Radio head is a control unit and the radio receiver in the rear part of the car, behind the right passenger seat. I ran wires under the seat and through the carpet to the back floor hatch. I plugged the OEM wire connectors and the car connectors and It worked. Also Connect the the blue wire on the OEM Amp connector to the Remote Turn-On wire on the Alpine Player. This will control the Power antenna and Factory Amp on the car. Don't connect the Power Ant wire on the player. The OEM Amplifier Intergration system is Fully Adjustable to get the best sound with you factory system.I shopped All over in Hawaii. And Everone I talk to said" I had to rewire the whole system and they were wrong". My car sounds great. You will not be disapointed. Also Shop Crutchfield, they have the Best Service and Free Shipping to Hawaii. I saved over $500.00 Because of the great service and tech support at Crutchfield.

thank you Scosche

Written By no, Savannah, GA on Thursday, January 31, 2008

Crutchfield Customer Review (What's this?)

This adapter works flawlessly, and saves the cost and time of completely re-wiring you vehicle. I used this adapter in a 1990 Corvette with the Bose Gold system to replace the head unit. I'm guessing as most of you with a Bose system already know, re-wiring your car is almost the only option you have, this thing is a life saver.........

Very easy install and setup, compact so its easy to hide, works flawlessly, saves you from re-wiring you entire vehicle, would definitely recommend it to anyone who just wants to change out the head unit.

Hands-on research

What's in the box?

Download owner's manual

  • OEA-4 OEM Amp interface (with 8-wire input with bare wires/8-wire output with white rectangular connector)
  • Flat-blade screwdriver (attached to interface module)
  • 13 Crimp caps
  • Instruction sheet

Product Research


Compatibility: The OEA-4 (model C4GM02) is a non-electronic interface that allows an aftermarket high-power stereo to integrate into select 1986-96 General Motors vehicles with Bose premium factory systems. Please check the Crutchfield Vehicle Selector for compatibility for your vehicle.

Adjustment Gain Controls: Four rotary gain controls (front left, front right, rear left, rear right) are located recessed inside the adapter chassis. There is a small flat-blade screwdriver attached to the adapter's case, and its use is recommended. The controls are very fragile and sensitive, and a slight adjustment will change volume dramatically.

Harnesses: The adapter's input wires are approximately 5-1/2" long with bare ends. These splice to the new receiver's speaker output wires. The adapter's output wires are approximately 11" long and terminate into a white rectangular Molex plug. There are 5 additional wires coming from the white plug that should be spliced to the receiver's wiring harness. The Molex plug end is molded to match with the factory wiring harness. Crimp caps are provided for wire splices.

Our Product Research Team

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