I have a 92 325is. The noise sounds a lot like alternator whine, but the voltage seems ok and no other electrical problems persist. It goes higher pitched with higher RPMs. I have heard that a defective dong (door chime etc) may set of a very similar noise, is there a way to disconnect it?
It is not coming from the stereo speakers. Since turning them on and off does not alter the noise. It seems like with the headlights on the noise is a bit louder. Which in return would suggest alternator whine again
The alternator has a rebuild sticker on it so I know it is not original.