Hello.
Hopefully, I've come to the right place for help. My '03 Aztek has been nothing short of superb. Up until June of this year all I've had done was brake pads and oil changes. In June, the front wheel bearings feel apart without warning, other than the anti-lock brake light coming on. The mechanic who did the repair was as shock as I was when he took the tire off. Anyway, that's not my issue today. About 3 weeks ago, the stereo quit. No sound, but it kept full display. When it came back, everything was "poppy and crackled", like a poor AM station in a thunderstorm. Then it put out a sound that I only can compare to a harpooned dolphin, turning it off doesn't stop it, only unplugging it. I was also getting an airbag light while the radio was going through this. I lost complete sound from the back speakers, very poor quality from the passenger side, and the door chimes and warning sounds are faint and static.

I did the un-hook the battery and remove fuse #28, no help. So, I purchased a replacement radio off eBay for $25. Only to find the wonders of GM Theftlock! After a trip to the dealership to unlock, which they didn't(That's another story), I found out that the radio can be tested before it goes into lock. The "new" radio does the same thing. Poor right side sound, no rear, faint door chime, then it goes nuts and gets the dogs in the neighborhood howling!

By leaving it unplugged, I have no other issues. No warning lights are on. But I need a stereo. Please, any help will go a long way in keeping my sanity. Driving with ear buds is getting ridiculous

I've checked and rechecked every ground, unplugged the front speakers and pulled fuses. It did seem to "work" for with the LF door speaker unplugged, however when I adjusted the volume and fader I lost everything again.

Would having the vehicle hooked to a Tech II at the dealership show the issue even though I'm not having any other symptoms or trouble codes?

I'm lost