Fibonacci

Folks, I'm getting a headache and a pain in my ears whenever I drive my '07 530xi. I've tracked it down to an extremely high frequency buzz coming from the speakers. It varys in intensity while I'm driving, but it's still there when I stop the engine.

At first I thought it was an air pressure problem, but continued investigation has led me to the sound system. The buzz is there whether the climate control system is on or off. It doesn't matter if the (Business CD) stereo is muted or not, or which input it is selected. However, when I turn the engine off, pull the key and wait for about 40-50 seconds, I hear a click from under the dashboard, a electronic pop from the speakers and it all goes away.

Based on the fact that BMW assist is tied into the speakers, as well as the phone system, I'm assuming that the power amplifier is always on, so if it were defective or improperly grounded, it could cause this problem. I believe that is what's turning off about 40 seconds after I pull the key.

At this point, what I'd like to do is pull the fuse on the power amp, and see if that helps. Maybe I should pull the fuse on a couple other things as well. Problem is: a) I haven't found the trunk fuse box yet and b) there are 6 or 7 fuses described on the fuse card as being related to the stereo.

BTW: In the front fuse box there are two fuses labeled for the stereo. Pulling the first (18) shut down the full instrument cluster and the IDrive, but the high frequency buzz remains. Pulling the 2nd (34), only shuts down the IDrive, but the buzz still remains.

I had a 2007 530i loaner for 3 days, and there was no such problem, so I know this is not a problem with all 530's!

Any suggestions?

JStraw

No specific suggestion, except to say that you should have a Service Center check it out and diagnose the problem.

subterFUSE

If it were only occurrnig when your stereo was on, I would probably say it was alternator noise.

But the way you describe it tells me otherwise.

Take it to the dealer.

Fibonacci

I will, but I'd like to be able to tell them exactly what's going on, so they don't do this and send me home like this

Heiss5

Well that's guaranteed to happen no matter what. You just have to keep bugging them over and over and over again until they finally give in and look into it. Then you have to bug them over and over and over again until they finally give in and fix it the first time. Then you have to repeat the process 3 more times before you decide to give up or continue to bug them about it for 3 more times. Then once you're ready to sell the car they will finally have a fix for your problem, but it will be too little too late. Either that, or they will tell you it's normal and that every model does it.

Fibonacci

That's exactly my fear, hence my interest in doing some traige before ever visiting the dealer. If I can tell them under what conditions it stops, perhaps they can figure out what needs to be replaced.

Which brings up back to the original questions:

a) Where exactly is the 'Trunk Fuse Box'?

b) Anyone know which fuse, specifically, protects the power amplifier?

POGI

a) remove the 2 push buttons on the right trunk trim and you will see the fuses and battery. Fuse location is listed on the tools/first aid holder by the trunk hood.