2004 GMC Envoy Car Radio Wiring Guide - ModifiedLife Whether your an expert GMC Envoy mobile electronics installer, GMC Envoy fanatic, or a novice GMC Envoy enthusiast with a 2004 GMC Envoy, a car stereo wiring diagram can save yourself a lot of time. Automotive wiring in a 2004 GMC Envoy vehicles are becoming increasing more difficult to identify due to the installation of Read More Read More 2004 GMC Envoy | Stereo Wiring Diagram 2004 GMC Envoy Stereo Wiring Information. Radio Battery Constant 12v+ Wire: Orange Radio Ground Wire: Black/White The stereo wiring diagram listed above is provided “as is” without any kind of warranty. Use of the information above is at your own risk. Leave a Reply.