Today I got the new deck hooked up to my 93 suburban. The dash speakers and the speakers in the side doors work but not the speakers above the tailgate. I believe I got the factory amp working by connecting the pink wire in the suburban to the wire on my deck with the description of "To system control terminal of the power amp or Auto-antenna relay control terminal." But I am unsure as I don't know what the factory amp is connected to. I cannot find a wiring diagram for the Suburban that includes the factory amp anywhere. Anyone willing to clear this up for me a bit would be awesome.

 

I know its been 2 years but I'm new to the forum but I just had the same problem. The factory amp controls the rear door speakers only the dash and roof speakers are controlled by the stereo, if the roof speakers aren't working it may be a wiring issue.