I also wired the audio cables from the Empeg cage (using a spare phone plug adaptor) to the BMW connector adaptor, which has leads for FR +/-, FL +/-, RR +/-, and RL +/-. Perhaps the problem is that the line-level plugs are not matched properly to the BMW HK amp? I would eventually like to replace the amp/speakers but for now thought I would start with the head unit. I'm going to hook up my voltmeter tomorrow to make sure it isn't a problem with the Empeg audio output.

Thanks,
David