Since I got my brother his 2005 Passat TDI about 2 years ago the rear speakers have never worked. I recently did a bunch of searching that narrowed the problem down to a bad amp or loose connectors; checking the connectors (at the doors and at the amp itself) did nothing so I'm thinking there's something wrong with the amp? Oddly I noticed there is a very faint sound coming from the rear tweeters but nothing from the actual door speakers. It's the factory Monsoon system, I've read how it's a pretty "proprietary" system and difficult to modify with aftermarket parts; I'm not looking to upgrade the sound at least for now, I just want the rear speakers working again. I found lots of replacement amps on eBay but I'm leary to spend money on another factory unit just to have it fail like this one did (?). Is there a fix for this aside from ripping out the stock head unit and amp and putting in a custom system?