I am trying to install a Jensen cd player in my 88 735i. I cannot get ANYHTHING to come out of ANY speakers. I have tried everything I can think of. I took a speaker out and put the wires from the cd player to the speaker directly and got sound, so I know the speakers are good. And does anyone know hat the little knob to the right of the steering column with an icon of a speaker about and below it means? I'm stumped. Anybody put an aftermarket unit into thier BMW? any help would be GREATLY appreciated.