Possibly a failed final stage unit for the fan. Try performing a key off draw test with an ammeter to find the draw. That model should be no more than 50 milliamp. As to the radio code issue, BMW has made it difficult to obtain radio codes for their radios. There is a process that requires submitting a case file and can only be done by the dealer. I have taken to replacing the old BMW radios with more modern equipment. See crutchfields. Com for a place to start, or go to the dealer.