Hi, I have an A4, 2002, 1.9TDI Quattro, Estate. I recently bought a new HU for the car (JVC KD - R541E) , stripped the old Audi Concert HU, hooked her up, front speakers are working, but the rear speakers and sub aren't working. The sound system is BOSE. I bought an adadpter to attatch all the cables in the right places, all I'm left with is a blue wire, that says "Amp power up 12v" (Or something along those lines) Is there any way to get all the speakers and sub working as they were before I removed the OEM HU. I've looked at many different threads on this, and they were all a bit vague, can anyone enlighten me?