Hello all, I have a question on the main audio amplifier. We've started hearing what sounds like a wiring short in the audio system. Even with the stock head unit turned OFF we still get a nasty thumping through the speaker that happens occasionally. It's very loud and happens with the stereo on or off It started about 6 months ago and we thought the stock Bose speakers were going out. Swapped out all six for Alpines and put a new Alpine amp in to power them. The problem persists. The guys that installed the system pointed me to this main audio amplifier unit as likely failing. I do trust these guys as they've done work on my other cars. They'll install the new audio amp for free if I bring them a new one to install.

I called the dealership and it's PN: 20811234 and runs $391.00. Yikes. I do see it on eBay and GM Parts Direct for about 40% less, but I'm not sure if that's a good idea. So here are my questions for the pro's here on the Forum:
* Does this sound like a main amp issue to you?
* Would you endorse getting one of these from a cheaper source like eBay or GM PD?
* Is there something I'm overlooking?

Thanks,
Jeff

 

GM parts direct is a GM dealership in North Carolina. Anything you get from them is the same as what you'd get from your local dealership. I've bought a lot of stuff from them, and they're gtg - just keep an eye on your shipping costs. It seems to me that's where they make their money. They have the lowest prices usually, but after shipping, they're sometimes more expensive than other places.

Is there any pattern to when the noise shows up? Bumps, certain engine speed, conditions, etc? Is it out of all the speakers, just the sub, some speakers?

 

Thanks for the reply. Glad to hear GM Direct is gtg. I'll watch out for the shipping costs.
Regarding the issue itself, it seems to happen after we've been on the road for more than 1 hour. It's very loud when it shorts out and I'm pretty sure it's coming out of all the speakers. Keep in mind that happens when the head unit is turned OFF too! Thoughts?

 

137 views, and InTheBurbs is the only response to this? Nobody was experienced this before or knows what it is?

 

Sounds like maybe something is heating up and then causes problems. The amp sounds like as good of a possibility as any.

Amazon has it for $197.68 here -
I guess I'd probably buy it, install it, see if that solves the issue, and if it doesn't, return it.