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      11-12-2010, 11:28 AM   #1

Drives: 2007 328i
Join Date: May 2010
Location: Columbus, OH

iTrader: (0)

Help requested diagnosing a noise

I have heard a buzz/hum that sounds somewhat "electronic" that only last about a second then repeats. For example, it will start when I coast or accelerate. After spending some time trying to pinpoint, I think the A/C or heat needs to be on for it to make the noise.

If I have the fan off and press the snowflake to turn the a/c on, sometimes it will make the hum noise. However when I have the car parked and press the snowflake, I do not hear the hum.

Also, I have noticed that the noise appears sometimes if I come to a stop and while stopped I can get the noise to start and stop if I adjust how hard / weak I press the brake. I don't think it is related to the breaks though.
Considering the car is an 07, I'm hoping it could be a belt or pulley making the noise. Worried I won't be able to replicate while at the dealer.

Reaching out to the forum in case anyone has any ideas or has encountered a similar noise. Any help would be appreciated.