My 2008 R55 Clubman with base radio has stopped receiving all AM stations. FM seems relatively unaffected. I am able to receive only the two 50,000 watt locals, and those two are nearly unlistenable due to the tremendous static. There was no work done shortly before the failure, though the head unit was replaced under warranty probably a year before the symptom occurred. Whip antenna was replaced, but still no joy.

I know at least a few of the possible culprits:
1. possible diversity antenna amplifier failure
2. antenna connection issue somewhere - at HU, trap, diversity, etc.
3. trap circuit?

Questions:
1. Where is the diversity amplifier in the Clubman? Others have asked this before (yes, I searched) but no answer has yet been posted. Anyone BTDT? Penske and realoem.com show the R56 diagram only; nothing for R55 even after VIN input.
2. Short of paying the dealer, is there any way to test the diversity amp's functionality?
3. Is there a way to bypass the diversity amp? Not really interested in paying $250+ to get AM, especially if it can be bypassed. Yes, I know what the diversity amp is for and that reception will not be as good. But lots of cars do without, and I am fine with that.
4. What does the trap circuit do? Is this a possible cause? If so, is there a way to test this?

I plan to try some deoxit at the diversity amp. See http://blog.bavauto.com/10056/bmw-po...-other-models/

Thanks for any and all input!

Will

 

I have the same symptom in my '08 Clubman. Occasionally, I can get some AM reception.