I'm giving myself a headache trying to read those factory wiring diagrams...

In an '01 Avant (non-Bose), am I correct in assuming that the signal for the rear door speakers goes through the subwoofer first?

Right now, I only get very occasional sound from the rear speakers and subwoofer, but the front speakers work fine all the time. When the rear sound cuts out, there's a distinct "click" from the vicinity of the subwoofer. Then there are subsequent clicks, but they don't always correlate with the sound coming/going.

I've got the factory OEM sound system with all OEM sound equipment, nothing's been modified (although that will soon change if I can't fix this easily).

 

If you have non Bose, there is no subwoofer.

 

It's an Avant, there is a subwoofer, even in non-Bose.

Heck, I had the subwoofer in my hands. I can't make this stuff up.

 

Might help with your clicking noise heard? Seems like you blew something or something isn't wired correctly or loose.

Subwoofer Makes Clicking Noise When The Volumes Up? - Yahoo! Answers

 

It's all factory wiring and I checked the voltages at each pin of the wiring harness at the subwoofer. It's all right where it should be. Also, there's no gain to be adjusted. This is the factory subwoofer. No adjustments anywhere.

It seems like there's a really crappy amp built into the subwoofer, and I have a feeling it may be defective due to some recent water damage.

 

I think the amp controls just the rear speakers ad sub nothing to do with the front so you would be right in assuming the amp is baf

 

Yeah, all the diagnosing I've done seems to point to a bad amp in the tupperware subwoofer. There were also a lot of chewed wires in there from a residing squirrel/mouse.

Oh well, time to go custom I guess. Good thing the Symphony head unit makes it so easy to add external amps.