550iNZ

Hi folks


A non-urgent mystery I am trying to solve.


I'm driving my e61 550i along in the rural countryside (far from any transmission antennas unless they are exceptionally well hidden in the pasture) listening to a CD (not radio) via the OEM stereo, then I get a loud harsh pulsing static burst sound that lasts probably just under 2 seconds. It sounds similar to the interference sound a cell phone makes when it connects to the network when receiving a call, but it is more harsh and static and higher pitched vs the lower tone interference a cell phone makes. This isn't a scratched or skipping CD sound, not remotely.


I don't own ANY mobile devices or have bluetooth or anything similar installed in the car.


My guess is that every so often (maybe once a week or two or every third trip out in the car) some electronic event occurs in the car's electronics which results in the CD player or amplifier for that brief period having interference. Another thought I had is that overhead power lines may somehow occasionally pulse some kind of power surge/harmonic pollution or power-line communication that is causing the interference of the CD player, but if this is the case it would have to be exceptionally strong since we're talking about a CD player and not an AM or FM radio receiver directly amplifying the radio spectrum.



Any ideas?


Cheers

Warren

Anthro

Years ago in a different vehicle I had something like the noise you are describing when the terminals on the door speakers intermittently grounded on the metal of the door.

​​​​I am not suggesting you have this problem. I am just saying that all kinds of wiring troubles could cause that kind of sound.

550iNZ

Thanks Anthro. The plot thickens! Will check potential wiring issues. Tailgate glass micro switch has recently gone so wonder if it could be tripping something.