Hey problem solvers (stereo)

[Rider90]

...This isn't Marauder related, I know, but it is stereo related and I know we have some gurus in-house.

I purchased this head unit, Pioneer DEH-P7800MP (http://www.pioneerelectronics.com/pna/v3/pg/product/details/0,,2076_310069880_291147601,00 .html), for the 99 Tahoe I've been driving. I installed it yesterday but for whatever reason, none of the rear speakers work. The fronts work great, but thats all.

I tackled the troubleshooting a little bit ago and here is what I found:

1) I bridged the connection from the head unit front left speaker + - to the in-dash rear left speaker + - and did not get any sound from the rear.

2) I put the factory head unit back in and voila! Sound in the front and rear speakers. This rules out any faulty wiring from the dash connection to the speakers.

3) I probed the left rear + - connections coming from the aftermarket head unit and I have power (signal).

4) Suspecting a possible connector problem, I bridged the connections from the headunit left rear + - and hooked them up to the in-dash left rear + - connections. Still no sound from the rear speakers.

So even if I forcibly take the speaker signal from the aftermarket head unit, that successfully gave the front left speaker it's sound - and connect it to the rear left speaker + - I cannot get sound.

:confused:

[BAD MERC]

First, chevy sucks more than anything that has ever sucked before. Second; Does it have Bose? OnStar? Rear audio controls? That should be a plug and play with a 70-1858 metra harness. If you have any of the other stuff, it may require an integration module such as a GMOS1 or a complete Bose rewire. Call me if you need to, 239-770-3630 Saturday only. I will be at my shop in the early AM (10ish) so call me and I will do some homework while I have you on the line. If you cut the wires then here they are; tan LF+, gray LF-. Light green, RF+, Dark green RF-. Dark blue, RR+, Light blue RR-. Brown, LR+, Yellow, LR-. Orange, batt12V. yellow, ign12V. black, GND. Pink, pwr antenna. Gray, dimmer. There are TWO yellows and two grays.

[Rider90]

No bose, no onstar, no rear audio control. Real basic, 'cept for the CD player mounted in the cubby. I double checked the wiring, in fact the colors are identical from the Metra BB-WHGM2 connector and the Pioneer diagram. I don't know if another connector would help me out, seeing as I bridged the connections that were problematic, and the problem was not solved. IIRC, I bridged the Green & Green/Black (Pioneer side) to the Brown/Yellow (OEM Side) and still no sound from the rears. Hooked the factory head unit it up and they work. Even swapped the connections for the front and rears to see if I could get sound, and nope. I don't know what I'm missing...

[Grifter]

on the pioneer HU, do you have the power antenna/remote turn on wire connected to anything in the harness on the car side? There might be factory amps that are not being turned on. I am not super familiar with GM stuff, but thats where i would start.

[Rider90]

on the pioneer HU, do you have the power antenna/remote turn on wire connected to anything in the harness on the car side? There might be factory amps that are not being turned on. I am not super familiar with GM stuff, but thats where i would start.
I do not...hmmmmm!

[rvaldez1]

Jason, I am very familiar with that model and year. The CD changer in the cubby hole will not affect the functionality of the speakers. You definitely do not have an amp, cause the '99 Yukon SLE I worked on had only a Delco radio and six speakers. Double check the wire connections, and make sure the pins on the harness are not bent. What I would do is double check the Fader on the aftermarket stereo I know its like a dummy step, but you never know. If that doesnt work.
Connect the the rear speaker outputs on the aftermarket stereo to the FRONT speakers. If you get no sound from the front speakers it is the radio. To me I would put my money on the radio being toast.

[Rider90]

Jason, I am very familiar with that model and year. The CD changer in the cubby hole will not affect the functionality of the speakers. You definitely do not have an amp, cause the '99 Yukon SLE I worked on had only a Delco radio and six speakers. Double check the wire connections, and make sure the pins on the harness are not bent. What I would do is double check the Fader on the aftermarket stereo I know its like a dummy step, but you never know. If that doesnt work.
Connect the the rear speaker outputs on the aftermarket stereo to the FRONT speakers. If you get no sound from the front speakers it is the radio. To me I would put my money on the radio being toast.

Could the Pioneer really be toast if there is power being sent TO the rear speakers?

[ctrlraven]

Is their a function that turns off the rear speakers like our MM stock radio does with the DPS button function? I know what Pioneer unit your talking about, I just can't remember recall it's extra functions.

[Lowell]

Hook up your amp trigger to power ant lead on your harness adapter. These vehicles are amped for the rear doors and head liner speakers. Problem solved. Need more info pm me.

[magindat]

on the pioneer HU, do you have the power antenna/remote turn on wire connected to anything in the harness on the car side? There might be factory amps that are not being turned on. I am not super familiar with GM stuff, but thats where i would start.

Not an issue unless bose or on-star present. Also NO speakers would work.

[magindat]

Is their a function that turns off the rear speakers like our MM stock radio does with the DPS button function? I know what Pioneer unit your talking about, I just can't remember recall it's extra functions.

Yep. They can be turned off, run full range, set as 'subs', or high passed.

[Rider90]

I wanted to let everybody know the problem is solved, you guys are da best!

Lowell hit it right on the head but thank you to everyone that responded!

[Grifter]

Not an issue unless bose or on-star present. Also NO speakers would work.

Not all speakers in every car are amped. This is one of them evidently.
Its GM it doesnt have to make sense.

[magindat]

Its GM it doesnt have to make sense.
Obviously got a point there!!!!

BTW, GM also runs airbag thru the radio on some models. Why?!

[Breadfan]

Obviously got a point there!!!!

BTW, GM also runs airbag thru the radio on some models. Why?!

Maybe it mutes the radio when the airbag goes off? I mean, if you're airbag goes off you probably ought to turn down the tunes anyway... :o

Sersiouly though, could be part of onstar maybe...??