I have a BMW 530D 2002- a few weeks ago my FM radio, cd player, tape player and TV all stopped working. When I turn any of these on I get a loud high pitch noise coming out of my speakers similar to that of a loud modem\fax machine tone. The weird thing is the audio all works fine on the following, AM radio, SAT NAV and Bluetooth hands free. Also over the last few days my dashboard background lights (the ones that can usually be dimmed) seem to intermittently come on and off, more so driving over bumps. Any ideas welcome. Could this have anything to do with the ignition switch?