2003 GMC Sierra Radio Wiring Harness
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URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=113344
Printed Date: May 19, 2025 at 5:07 AM
Topic: 2003 GMC Sierra Radio Wiring Harness
Posted By: austin881
Subject: 2003 GMC Sierra Radio Wiring Harness
Date Posted: April 22, 2009 at 4:28 PM
I need some help finding a wiring harness for my 2003 GMC Sierra. I would like to install an aftermarket head unit but I've been told by Metra Electronics/Axxess and Scosche that I have some special wiring harness that so far everyone is baffled by.
Please see this link for photos:
https://www.maddoxspace.com/images/wiringharness/
* No OnStar is present in the vehicle.
* No Standard or Premium Bose system is present.
* I've tried both the Metra Electronics GMRC-01 and GMRC-02 wiring harnesses, neither of which fit my truck.
* Metra tech support tells me that I have a Chevy Malibu harness coming out of the vehicle.
* Scosche tech support tells me that I have a rare Class II, 11 bit harness coming out of the vehicle.
Will someone please advise me if there is any wiring harness that will fit my vehicle? Thank you!
The above photo depicts the problem. The grooves in the GMRC-02 do not line up with my wiring harness. Close by no cigar. The GMRC-01 is the same way.
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2003 GMC Sierra | Ext Cab | 5.3L V8 | No OnStar | No Bose
Please see this link for photos:
https://www.maddoxspace.com/images/wiringharness/
* No OnStar is present in the vehicle.
* No Standard or Premium Bose system is present.
* I've tried both the Metra Electronics GMRC-01 and GMRC-02 wiring harnesses, neither of which fit my truck.
* Metra tech support tells me that I have a Chevy Malibu harness coming out of the vehicle.
* Scosche tech support tells me that I have a rare Class II, 11 bit harness coming out of the vehicle.
Will someone please advise me if there is any wiring harness that will fit my vehicle? Thank you!
The above photo depicts the problem. The grooves in the GMRC-02 do not line up with my wiring harness. Close by no cigar. The GMRC-01 is the same way.
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2003 GMC Sierra | Ext Cab | 5.3L V8 | No OnStar | No Bose
Replies:
Posted By: howie ll
Date Posted: April 22, 2009 at 4:37 PM
Posted By: austin881
Date Posted: April 22, 2009 at 4:45 PM
Is there an acronym guide somewhere so I can understand what you just wrote? 
CAN?
DMM?
Must I really resort to soldering to the new head unit's plug? Here I thought I drove the most common pickup truck on the road, a GMC Sierra. This is just astounding that the wiring harness is such a one-of-a-kind. Is it possible that the wiring harness was somehow changed out at the dealership by the previous owner or something? I'm at a loss.
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2003 GMC Sierra | Ext Cab | 5.3L V8 | No OnStar | No Bose
CAN?
DMM?
Must I really resort to soldering to the new head unit's plug? Here I thought I drove the most common pickup truck on the road, a GMC Sierra. This is just astounding that the wiring harness is such a one-of-a-kind. Is it possible that the wiring harness was somehow changed out at the dealership by the previous owner or something? I'm at a loss.
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2003 GMC Sierra | Ext Cab | 5.3L V8 | No OnStar | No Bose
Posted By: howie ll
Date Posted: April 22, 2009 at 6:17 PM