1996 GMC Suburban Stereo Wiring

I've searched and searched and can't find what I'm looking for.  Ok...My mom just bought a used 1996 Suburban in near showroom condition.  Well, the original owner had hacked the original stereo harness up for an aftermarket head unit.  Well, it was stolen and left without any stereo.  The dealer has since reattached the factory harness and put the OEM stereo back in.  Both front door speakers (well, there's also two tweeters up there too) are working fine.  The back door speakers do nothing at all.  And only the left far rear roof mounted cargo area 4x10s is working.  I'll work on that later.  I think it's a lose connection somwehere.  Anyway, I can't figure out why neithr of the back door speakers are working????  And I can't find a wiring diagram that even mentions these speakers.  I've double checked the repair job on the OEM harness and everything looks good.  I just don't know which wires to focus on for the rear speakers????  Anyone have any idea what I'm talking about?

Thanks,

Robert

speakers are as follows... positive first neg second

lft.ft. --cream       grey

rt. frt. --lt. green     drk. green

lft. rear--- yellow     brown

rt. rear------lt. blue   drk. blue

Well, I'm a little bit closer.  I found that the far right rear cargo 4x10 is blown and completely DOA.  I'll search for another soon.

I also found that the front door tweeters were unplugged for some reason.  They're working now.  As for the rear door speakers, I found that they had been cut in the b-pillars and re-routed to the rear apparently for an amp that's no longer there.  I re-attached them and now the right rear speaker is working (dosn't sound that good but probably has to do with the dead 4x10) but nothing form the left door.  I can't seem to track down where they are spliced parallel.  I tracked to the driver kick pannel but that's as far as I could go.  I tried using an ohms meter to check from the stereo plug to the left rear leads and get nothing on either wire.  Also, the wires on the left rear door aren't exactly the same colors...looks like white and a light tan not the yellow/dark brown as the rear 4x10.  Any ideas?

Thanks,

Robert

Woa. Are you talking about an external factory amp other than the head unit?  Where would it be?  I thought everything was in the head unit because of it's beefy heatsinks and fan.  However, I'm thinking that if it does have an external amp, it must still be in there because I'm getting sound from the right rear door.  Wait, but that sorta makes sense too.  The sound from the right rear door isn't very good.  Low power and sorta distorted. Just a guess but maybe since the right rear is blown, it's sending juice back to the door??  And since the far left rear is working, the door isn't getting anything.  I don't think I saw a pink lead up front.  I think that they had spliced in to a yellow wire for a remote amp turn on tho.  Now I'm even more confused...I'll hafta get back in there in the next day or so and dig for that amp and remote lead.  Just need to know where it may be...

Thanks,

Robert

Awesome...I had found it under the driver seat before you had posted again.  I had seen that lil silver aluminum thing a while back but didn't think twice about it because it didn't look like an amp.  This time I felt it and it was warm.  I checked out the wires and saw that some matched.  One of the plug terminals had pushed back into the amp and lost contact.  I pulled it apart and it's working great.  It's obvious that more attention to sound quality was used up front.  The fronts with the tweeters sound awesome.  The back seats are just ok.  Thanks a bunch for all your help.  Now, I've just gotta find a replacement Delco 4x10 for the right rear.

Thanks a ton!

Robert