The car has the 8 speaker setup, also with on star. The radio appears to work fine ( tested with another) I have no sound what so ever, no door chime, nothing. Does this sound like a monsoon amp problem? I have checked all fuses, replaced both door modules, checked all connections at radio, front speakers, amp, anntana module in trunk. Im starting to bang my head against the wall Any help is greatly appreciated.

And when did GM start useing monsoon and bose together? I noticed the radio is bose and the amp and 2 rear deck speakers are monsoon.

At the Audio Amplifier disconnect C2 and check for ( b+) across pins H (b+), and A (grnd). You should be looking at 12-13 volts ign off. This power supplied from fuse #63 (20A) in the rear fuse block. You can also disconnect C1 at the Audio Amplifier to check for the 14 volt reference signal on pin A1to ground.

In lamans terms? What am I checking for, low or no power?

You're checking power & ground. You'll need a multimeter selected to a DC voltage scale that will accurately read like 10 to 15 volts DC. At the C2 coinnector which makes up to the Audio Amplifier place meter across pins H & A to read the 12-14vdc battery supply. Then at C1 place meter positive in A1, meter negative to car chassis, should see the 14vdc reference.

Though Mark is a smart Man,
Im moving to Audio so others may give input as well.

OK ill try that and let you know. Thanks.

Wow Jim, thanks for the kind words. I would agree, this topic needs more exposure to the Audio Wizards, Electronics Techs. & Chip Heads.

I believe we are not even getting 1 volt on H across A and like 2.5 volts on C1 at A1 to ground. I checked the fuse and fuse box and im getting 12 volts. It seems like a break in the line in that short distance from the fuse box to the amp, but I really daubt it. What do you think?

Yeah im lost also I guess I have to start playing the guessing game, so I have an AMP on the way. Hope that works, the guessing game is tuff on the walet.

Im still wondering maybe if the onstar has somthing to do with the problem, knowing it uses the audio system to work. I tried the onstar and it looked like it was working, but couldn't hear anyone talking.

This car has been welded on so I was thinking maybe somthing electronic could have shorted out, who knows.

Where did the welding take place? Was it stick, TIG, MIG? Welding process can have adverse effects on electronic equipment when the welding is in real close proximity. Your previous post indicate that you're not getting power to the audio amplifier, don't get an amp yet, find out why power is not getting to the existing amp.