Neewbie Questions About Factory Sub Wiring

[wild willy]

Hi! Relative newcomer here, just upgraded from a '97 S10 Blazer to a 2002 Tahoe Z71 that is pretty interesting. It was ordered as a police vehicle, and has some odd things going on- like no foglights, though it has the Z71 RPO code- it has dual speakers in the front doors, and I have replaced the AM/FM with a GM CD player- there doesn't seem to be an amplifier behind the glovebox, as I have read about in my searches here. There is existing wiring in the "D" pillars and for a factory subwoofer, though no speakers- I am trying to install the rearmost speakers, but I am not sure where the existing wiring harness terminates. I didn't see a plug behind the glovebox, did I not look hard enough? Or does it end somewhere else? I suppose I could tap into the speakers in the rear doors, unless there is a better, more elegant way of doing it. Anybody done this before, and have some useful info- Thanks for the guidance- I have thought about going to a salvage yard and getting the factory amp, but if the wiring for it isn't run, it would be just as easy to run new wiring and go aftermarket, at least in the back.

[wild willy]

Nobody knows where the factory harness for these rearmost speaker begins? I would like to tap into it, to drive either factory speakers or aftermarket-

[wild willy]

Anybody use a PAC connector to tap into the rear speakers? If I go that route, will I still have the read speakers in the door, as well as the new rear subs and tweeters?