Bypassing factory FM antenna
 

Problem: FM signal is gone (all stations) when I turn on the rear defroster.

I've tried everything that is easily replaceable/accessible:

New radio module (in the trunk)
New supression filters in the upper hatch
Cleaned all contacts with Deoxit.

So at this point I was wondering if I can just bypass the antenna all together.

Basically get an oem antenna adapter used for aftermarket radios and get my own powered antenna that I will mount it somewhere?

Maybe even get creative and put a fake shark fin antenna and retrofit the fm antenna in there some how?


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there is a previous thread on this. QS put up a really good diagram on how the whole antenna system works.

Yes I know about the entire antenna and diagrams but still no fm signal so now looking to ditch for an aftermarket.


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last week I finally discovered there was a link between radio not working and using the rear window defroster.

I'll watch your thread for possible fixes and for now will just no use the radio during the 5-10 minutes the rear defroster is on.

Rich

I've had similar problems when using USB power adapters. radio frequency noise in crappy Electronics. I would maybe try to add a choke on the power to the defroster. I'm betting BMW built one in the circuitry and a part failed and no longer removes the noise or broke in a way to start adding noise. I'm not sure if the defrost is pwm or full on.

I think the antenna traces and defroster traces overlap on the glass and something happens to short them together. In a previous thread someone did replace the rear glass and it fixed the problem. I wouldn't think it would be that hard to locate the problem and maybe repair it.

Ok I think I was successful in this fix.

I bought an antenna adapter and a new antenna and basically completely bypassed the factory antenna, I just left it disconnected.

Now when I turn on the defroster my main station (100.3) gets very little static but goes in and out but it's very faint and liveable for sure. More like noise than static.

All other stations seem to work great now.

I haven't fully mounted the antenna until I am sure it works as I drive around more. Will also need to clean up my install as well.

This is much better than losing all FM signal for sure.


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