I own a 2010 328i Xdrive, 4dr. Upon entering the car I hear a crackling, humming noice coming from the dashboard. Upon starting the engine I hear a high pitched noice, like a whistle, also coming from the dashboard or speakers? This noice is there as long as the motor runs. When I shut off the engine and remove the key fob the first noice stays for a while longer until I hear like a shut off of sorts. Then the car is quite. When I open the door that noice comes back. Has anyone got a clue about it? BMW dealer wants to charge 350 $ for diagnostic alone. It’s literally driving me crazy. Thank you for any suggestions. Dominique.
