Can anyone tell me why the rear roof speakers in my 540i auto touring 1995 uk model are not working...I have just bought it....i have checked sound coming from the rear of the head unit and we have sound here, the original wiring is present at the head unit end and speaker end , all stereo settings have been checked and front speakers work correctly....any ideas?? i'm thinking there may be a connecter plug somewhere half way between the two which may have been disconnected, this is a guess, is there one or anything else before I start ripping my interior out and tracing wireing or running new cables???