I found that by grounding the radio directly the interference stops when the car is off. However I still have interference when the car is running. It doesn't appear to be RPM related. Does anybody have any thoughts.
I have a 2000 323i that I just put in a new Alpine head unit. The AM and FM reception is still degraded greatly when the defroster / defogger is on, but I thought I only reconnected the FM antenna and left the cable that I thought was the AM laying unconnected. So I have to question what that rougue cable is as it doesn't seem to affect anything negatively. MAybe that was the cable from my steering wheel controls and the FM and AM share the same antenna connection to the HU. Either way, I'm thinking that if I disconnect the AM from the rear defroster / defogger, then I'll have cut the link between it and the two radio band circuits. Does anyone think I'll be able to put a replacement AM antenna somewhere on the car (By the license plate? to alleviate this problem? I spoke to a dealer and they wanted to replace the rear window. No money for that job...
I'd appreciate any help. Thanks!
I did check that and the problem is no worse than before I changed the HU. In fact my AM reception has improved, but the defroster will still wipe out Am and degrade FM when I turn it on.