Have a problem with the radio.---The message on the monitor reads "THE HEAD UNIT IS NOT
CODED CORRECTLY"---the radio unit was repaired by an approved BMW radio centre. The
amp was checked and found to be ok---the local BMW dealership was of no help---another
technician says that the bus cable to the radio is faulty as the is no light on the cable ((whatever that means).There is light at the amp--and there is light at the C.D. player but no light at the radio
cable----Please help.