Audio Systems: Rear speakers not working, factory wiring harness, gmc jimmy

Question
I recently bought a 2000 GMC Jimmy and the previous owner had a "system" in the back which they removed prior to the sale but the rear speakers and the dash speakers do not work.  Also if I turn the fader switch to the front speakers the sound is completely gone. Only the speakers in the front doors work. Is it not hooked up correctly? And is it on the back of the stereo or the speakers themselves where the problem is?
Thanks,  

Answer
Tom,
Your first step would be to remove the stereo and if your local dealer will print one out for you, ask for the stereo connector wiring in the dash. With this you can use an ohm meter and test each speaker feed to see if they all have a good connection/continuity back to the speakers. It may only be that the previous owner clipped the wires from the factory wiring harness for speakers to use for the other system that was installed.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net