I'm trying to troubleshoot a problem for my father in law. His 99 A6 has the Concert system. It lights up when turned on but no sound plays through any of the speakers. I thought I heard a little fuzz when I cranked it up but it was too faint to be sure what it was. The fuses all seem fine and I've removed the unit as per another postings suggestion but nothing has worked. Please offer any advise you may have. Thanks.
