Hi,E39 1999 'V' Reg. Every now and then the sound will go on my system and sometimes it won't work for a week then it will come back again. I'm not sure if its the analogue TV tuner or a wiring fault. I think mine is the Professional system as opposed to the Business system,. The part number of mine is 6 902 015 and I dont seem to be able to locate this part anywhere. Does any one know if this part ( if at fault ) can be repaired. Thanks for any help.