Scosche CGM01 Wiring Interface

Allows you to connect a new car stereo and retain the factory amp in select 1982-up GM vehicles

Item #: 142C4GM01

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4 Reviews

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The Scosche CGM01 wiring interface allows you to integrate a high-powered aftermarket receiver into select 1982-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, then check here for a list of parts. You can also call an Advisor for more information.

Hands-on research

What's in the box?

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  • OEA-4 OEM Amp interface (with 8-wire input with bare wires/8-wire output with black rectangular connector)
  • Vehicle power wiring adapter (white connector with one yellow 6" wire)
  • Flat-blade screwdriver (attached to interface module)
  • 13 Crimp caps
  • Instruction sheet

Product Research


Compatibility: The OEA-4 (model C4GM01) is a non-electronic interface that allows an aftermarket high-power stereo to integrate into select 1982-89 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 black rectangular Molex plug. There are also 4 additional wires coming from the black connector that should be spliced to the new receiver's harness. There is an additional white Molex plug with one yellow  6" wire for the constant power connection to the receiver. The two Molex plug ends are molded to match with factory wiring harnesses. Crimp caps are provided for wire splices.

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Scosche CGM01 Wiring Interface Reviews

Average Customer Review:

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Needs more installation info

Written By DJ, Idahio on Monday, May 23, 2011

Crutchfield Customer Review (What's this?)

The color coding of each wire makes this very easy to install. However the guide was inaccurate when it said that the pink wire was not used. Turns out after reading online that the pink wire is the on/off wire for the Bose amplifier to each speaker. Had I not found this out online, I would not have been able to complete the install. Also the adjustment buttons for the gain are rather weak and could be stronger. Other than that...the instructions were good and the color coding makes it virtually impossible to mess up.

Great product

Written By Kaiser, Oklahoma City on Tuesday, November 16, 2010

Crutchfield Customer Review (What's this?)

Overall was a great install. All wires were perfectly color coded.
This went in a 1985 Corvette.
Only had an issue with one wire. There is a pink wire on the factory harness and
no lead from This harness. I had to cut the original from the radio and install
it directly to my radios amp wire. Basically building a simple harness for the
factory amp.
I called support here when I wasn't sure where the wire went and they knew
exactly what I needed to do. I did break one of the pots when turning it down,
but got another one and a few minutes soldering the new pot and all
was well. Total install time was around 15 minutes without the solder job included.
Be careful when turning down the pots they break off easily.

4 stars since it didn't have the amp lead built in. otherwise perfect product.

Scosche CGM01 Wiring Interface

Written By wayne, PA. on Friday, August 27, 2010

Crutchfield Customer Review (What's this?)

I am not good at auto wiring so when i opened the adapter i was a little
with all the wires i used the supplied crimps to connect the color coded wires.
I had two problems i thought one of the ground wires would have to go to ground
on the car but i called and you only have to connect the two ground wires together.
I had one wire remaining a blue wire it had to connect to the cars amplifier.
It took two phones calls and the help at Crutchfield was great ..They knew there
product very well... I would buy from them again in a heartbeat!!!!

Not enough connections - wires left over

Written By Mark, Johnstown, CO on Thursday, August 07, 2008

Crutchfield Customer Review (What's this?)

I don't know exactly if or how well the part works yet as I am still trying to figure out how to install it. I know how all the "existing" wires of this harness connect, but I still have three wires "left over" from the original installation. The wires that are left over are somehow related to my existing speakers and pre-amps, as when I disconnected them from my original radio, the speakers quite working. Unfortunately, the installation instructions received from Crutchfield do not address these "extra" wires in any way...the instructions are minimal and not specific to my particular car/system.

I'm going try to contact Crutchfield's support line this weekend to see if they can shed some light on this.

On the positive side, I'm sure learning alot about how stereo systems are installed since the instructions are so minimal and general, I've had to get out my volt meter and experiment with the wiring to understand what is what. Crutchfield's website gives you the impression that installing a stereo is easy, but I'm not finding that to be the case. It is interesting though!!

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