GMC Wiring Harness | eBay Find great deals on eBay for GMC Wiring Harness in Dash Parts. Shop with confidence. Skip to main content It plugs directly into your factory radio harness so you don't need to cut the original radio harness. The wiring harness adapter also has color-coded/labeled wires. 1986-2002 CHEVROLET GMC Stereo Replacement Wiring Harness Stereo wire harness cut, wires not matching diagrams wwweyukonforum››Audio & ElectronicsDec 08, 2016My stereo wire harness was spliced and rigged up so I went ahead and cut it off with plans to replace it. I looked up wire diagrams and color codes before I cut it, and it seemed pretty straight forward. The plan was to cut it off, then hook up (without a harness) an old head unit to see if the 4 door speakers need to be replaced.