Pioneer DEH-P77DH

I just recently bought a Pioneer DEH-P77DH. I can't get the rear speakers to sound, this has been installed into a 97 Chevy Tahoe. Has anyone installed the same head unit on any GM, is everything working right? 

I looked up your deck, and I noticed that it has a front image enhancer which is a low-pass crossover to the rear skeakers/pre-outs.  You may want to check and see if it's selected on the deck.

Did you use a wiring harness adapter?  If you did, you should double check that you've got the right one.  If you cut the factory harness off, I'd suggest running new speaker wire so you know that it's hooked up right.  You could also get the wiring schematic for your vehicle and double-check those connections, as they can be tricky to get right if you're guessing.

Thanks for your post. Based on the manuel it indicates that there is an option to activate the rear speakers. When I follow the steps to this option it is not there. I did use a GM harness without cutting any wires. All I get is front sound, I even tried removing the front spkr. wire from the harness and plug the rear and still no sound. I was told by Pioneer support that the GM wiring has the negative wiring joined to save money by the factory, there for it will require new wire to be runned. Thanks

The pioneer people are probably referring to a common ground speaker wiring setup, but I guarantee you your '97 Tahoe does not have a common ground system.

When you tested out the system have you physically stuck your ear up to the rear speaker and turned up the volume real loud?  Or have you only listened from up front?  Because sometimes it is very difficult to hear but there will be a faint bit of music when the FIE is turned on.  I know for a fact that that particular head unit DOES have this feature.  If I remember correctly you have to press "Audio" and then scroll through the list of different options (bass/treble, etc.) until you get to FIE.  Turn it on by pressing the Up arrow, and turn it off by pressing the down arrow.

Also, did you try hooking up the front speakers to the head unit's rear speaker outputs?  Because it is possible that there's a speaker shortt on the rear speaker wiring in the vehicle. Such a condition would cause at least the rear channels of the head unit to stop putting out any sound until the situation is rectified (i.e. once you eliminate the short in the wiring).  Some head units would mute sound to all of the speaker outputs while others will only mute sound to either the front or the rear outputs (depending on whether the short exists on the front speaker wiring or the rear speaker wiring.)

What I would recommend doing is using a tiny little test speaker to test both sets of speaker outputs of the head unit.  To do this properly you have to first disconnect them from the vehicle's wiring, leaving you with 8 bare wire ends running directly into the head unit.  Make sure none of them are touching each other or a spot of exposed metal in the vehicle.  Starting with the white and WHITE/ black wire, hook it up to your test speaker and see if you get output.  Then repeat with all of the 3 remaining pairs of speaker wires.  If all of them work fine, chances are the problem lies somewhere in the vehicle's wiring.

Next you'll want to do that same procedure again, but this time instead of using a test speaker, you'll want to use the wires in the wiring harness you purchased.  Try each pair of head unit speaker output wires with each pair of vehicle speaker wires, but do each pair individually.  Since it's highly unlikely that both rear speaker wires would have a short on them, if after that last test you get no output for either of the rear speaker's wires, I would probably conclude that there is a factory amplifier for the  rear speakers, and that it needs to get a turn-on signal.

if i am not mistaking the 97 tahoe had some models that had an amp much like the suburban and when the amp turn on isnt hooked up only the front speakers will play. if not use a dmm and test contunity to the rear speakers one might be grounded. but i think it is probably going to be the amp turn on wire