GM radio - factory color codes?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=1099
Printed Date: August 28, 2025 at 12:24 PM

Topic: GM radio - factory color codes?

Posted By: John Sellers
Subject: GM radio - factory color codes?
Date Posted: June 03, 2002 at 1:21 PM

Hello,

I have a question about factory colors for the stereo harness in my 1989 Chev K1500 truck. I've seen two different diagrams which differ in the colors for the right front speaker leads.

One diagram shows the +/- leads as Light Green and Dark Green respectively. The other diagram shows these two colors reversed from this - e.g. (+) is DARK Grn and (-) is LIGHT Grn.

Can anyone help confirm which is correct?

I don't have access for a factory service manual for this, and was hoping to avoid the expense of purchasing an aftermarket manual. I just want to replace the stereo and would like to confirm wiring before getting started.

By the way, I DO have an aftermarket converter plug/harness, but I thought it would be prudent to confirm the connections instead of blindly splicing and trusting the aftermarket piece. The aftermarket plug/harness has connection codes with it, but nowhere on the packaging does it confirm that it is indeed correct for MY vehicle.

Thanks in advance for any help.

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John Sellers

Replies:

Posted By: Big Dog
Date Posted: June 03, 2002 at 2:40 PM

Hey John,

The right front colors are definitely Light Green (+) and Dark Green (-) and has been since the days of the '70's . . . posted_image

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Prepare your future. It wasn't the lack of stones that killed the stone age.

Posted By: HotRod53F100
Date Posted: June 03, 2002 at 4:39 PM

Hi John, did you look on the top or bottom of the radio? Most GM radios of that era have the pin out punched in the metal cover. Also, be careful when splicing the wires, you will notice that GM uses 2 gray wires. One is for a speaker, one is for the face light dim. If you accidentally reverse them, you will wipe out a channel the first time you turn on yout headlights!

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HotRod

Posted By: John Sellers
Date Posted: June 03, 2002 at 7:14 PM

Thanks for the reply, guys.

HotRod, I haven't yet pulled the old radio. But I remember one out of an early 70's Buick that had the pin-out on the case, so I was hoping I'd find the same on this one.

Big Dog, you confirmed the other wiring diagram that I found. Actually, both of the diagrams I found had two separate color codes. Evidently, GM had two different harness plug configurations for '89-90 trucks. But only on one-half of one diagram did these switched colors for the right front speaker show. So I was hoping that it was just a typo mistake in the diagram. I've emailed the web-site owner to see if they will confirm this also.

Appreciate the help!!

John Sellers

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John Sellers