So I'm still dealing with this problem. I ended up just leaving the factory radio/cd/tape deck in, although all that worked properly was the radio. I got a couple more after market cd players, a Sony and a Clarion, tried those and same problem, no audio sound but everything else worked.
I was sick and off work for almost 2 years so this project was shelved but when I ended up being cleared to go back to work, I had to wire up a couple stereos in other chevy trucks and they worked out and there was more work involved in those ones since someone hacked the wiring out of the dash and I had to make everything work properly. So that made me want to get mine finished.
I went to Best Buy in Edmonton, they were out of the harness and module that I needed so I went to Visions in Edmonton and talked to their stereo guys. I ended up getting a PAC OS-2X, it is some new updated one that covers all the GM vehicles, it can do all the options OnStar, Bose, Nav, steering controls and it does just plain models with no radio options. We determined I have the base radio/cd/tape, no amp under console, no second harness, but I do have Bose speakers and Badging on the doors. I wonder if it has something to do with this truck being special ordered with goofy options like a 4.8 and 4.56 gears in the rear. I bough the truck used in 2010, but to this day I'm still finding weird stuff that just doesn't go together.
I wired up this harness interface, it has like 4 harnesses that plug into the main box, on for the chime and warnings, one to the radio, one to the truck harness and one for the amp which I don`t have. I removed my factory deck, plug this thing in with my JVC stereo, same problem I've always had, everything works except the audio sound. Chime works, lights up, off and on with the key, cd, but no sound. Antenna is hooked up, tried the cd, wondering if it was the radio part. Volume was not cranked up either when I plugged it in, nothing blew or tripped.
I Put the factory deck back in, the radio still works. I`m really getting fed up with this. I spent $260 on the stupid harness interface, and i still don`t have sound. The pins in the connector on this for the speakers match up to the truck wiring, I did notice they are different than the original module i got a few years ago.
If anyone knows anything about this problem or what to do i would really appreciate it. If not I might try hooking the cd player up direct without the interface, I know I won`t have the chime or warnings but maybe it will work. If not I have to get a new GM radio. They are expensive, and since mine has a cd and tape deck, I checked with GM about one with just the cd, they said my truck would have to have some reprogramming.