I recently purchased a 2007 H3 and had a leak in the sunroof. Fixed the leak and cleaned the drain tubes, but now the
radio is silent as are the door chimes. The radio has power and seems to function properly except for no sound. I have
checked all the fuses, as well as the speakers, head unit, and Monsoon amp. They seem to be functioning correctly as
well. My next thought was to remove the Body Control Module and inspect for damage, but I'm not sure if I will have to
reprogram the BCM after disconnecting from the battery. Any thoughts or recommendations would be greatly appreciated.

 

BCM? How did you verify amp and speakers "functioning correctly"? #38

 

Okay, so I'm realizing my radio diagnosing skills are not up to par. I know I'm getting power to the head unit because it turns
on and everything functions properly...volume, balance, fade...at least it shows these things changing...but still no sound. When
I unplug the main connector from the head unit, I hear a loud thump like the amp wants to make noise. I hear the same noise
when I unplug the C2 connector from the amp. I have connected some small pin inserts to the speaker wires at the head unit while the radio is
on and I get a reading of 3.75 volts, but no sound when I connect those same wires to an external speaker which I have tested with
a tone generator. I used the tone generator connected to the wires that go from the C2 amp out to the speakers to test every speaker
and they work fine. At least they make the desired tone. I'm not sure if I have a short or if the head unit is not outputting a signal.

 

Hummer-H3-Wiring-2007

 

well is it an aftermarket radio or oem? if aftermarket check the interface module. they do fail even when fresh out the box.

 

Test a known working speaker connected to any of the speaker outs, just run a temporary jumper that you can connect to a speaker.

If you still have the factory OEM speakers, they may all be toast. Happened to many of us over the years.

 

I have tested the speakers with a tone generator running a jumper into the back of the main wiring harness to the head unit. It seems like the amp is working fine
because the tone is very loud as I am doing this with the radio powered on. My hunch is that either the head unit is not outputting a signal to the amp or some
short in the wiring harness is preventing it from doing so. Can anyone tell me the best way to determine which is the correct answer? This is the original GM radio
part#15911397 with the 6-disc changer. The wiring diagram that Hummerz posted seems to correlate to my system perfectly.

 

Using a TG verifies wiring. Did you verify B+ at the amp from #38 and ground from G300?

 

Also, try turning off SVC, since there are 2 signals sent from the radio to the amp.

 

Is a tone generator a speaker? Like I said, test an actual speaker, if your speakers are toast, you wouldn't know that with a tone generator, would you?