Car Stereos: Aftermarket install 97 Yukon, car radio wiring, gmc yukon

Question
Installed a kenwood kdc-mp242, wiring harness adapter. The front door speakers and rear roof speakers work. The problem is the rear door speakers don't work. Hooked adapter per instructions.My question would be what color wires would the rear door speakers be on the factory plug? I have four in the factory plug (cd player separate plug) that lead to blind ends in the adapter, might these be the door speakers.I tried to put these wires into the rear output while unit was powered on and it went into protection mode.Will I have to splice them in to test them?

Answer
Dan,  It sounds like you might have the wrong wiring adapter.  Your wiring adapter should have the same amount of wire leads coming from it that your factory plug has in it.  If it does, then the instructions should explain what wires to hook up to the extra wires.  Otherwise, you can goto the following website and check your trucks wire colors and do your own wiring (which I do not recommend).  It is:
http://www.modifiedlife.com/1994-gmc-yukon-car-radio-wiring-guide/

Hope this helps, Scott