Thanks for posting Danzee, I had pulled the amp yesterday to see if the problem is there. But before I pull it apart I'd like to test your recommendation.
How would I go about testing the lines to the amp though? There are the two connectors, that connect to the amp in the trunk. I'm assuming one is coming from the head unit and the other out to the speakers. Does anyone have the wiring diagrams for these connectors?
Also, does anyone know if the 3 series and 5 series oem head units are interchangeable? If so then, Danzee I might just have to take you up on that offer.