2000 540i: Annoying electrical popping/clicking sound in dash

I've had my 540i for five years now. For the last two years I've been hearing an intermittent "popping" sound from the left side of the dash. It
sounds distinctly electrical, but there are no symptoms or problems with any of the car's electrical. I've had it in the shop twice, and they claim that they either can't hear the sound, or they say they can't see any evidence of problems when they got into the dash to investigate (between you and me - I doubt that they actually pulled the instrument cluster and looked, as they said).
Has anyone else experienced this?
It's not causing a problem with the car, but it's driving me absolutely batty. I've got very sensitive ears, and I don't think I should be hearing this sort of sound from the dash of a $61,000 luxury car.
BTW: It's not associated with the audio system, lights, turn signals, engine speed, or any other obvious sources. The sound happens randomly every 3-7 seconds, whether idling or driving at 70 mph. Hot or cold weather, rain or shine. IT'S DRIVING ME CRAZY!!!
HELP, SOMEONE!
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--
Arlelia & Ed
"Bill" < snipped-for-privacy@cnw.com> wrote in message
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If you have a cell phone, try turning it off. Cell phones do cause interference that can cause popping, etc., typically through the audio system, but sometimes the alarm enunciator.
Floyd
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Not sure about in a 2000, but in my (considerably older) 540i there is an electric motor and solenoid valve hung on the firewall on the left side of the engine compartment. Although it is not in the cabin under the dash, the sound they make may appear to be coming from that area. The reason I suggest it at all is this is the sort of cyclical popping sound that the control valve makes when it is regulating the heater core temperature. Does it only happen after the engine is up to temperature? Does it go away if you change the temperature set-point for max or min?
-Fred W
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I don't have a 540, but I would imagine there are a lot of things the same. I had this problem in my '96 740il and it turned out to be the stepper motors they use to control the heating vents. These are little motors located in several places near the heating vents that open or close them in response to where you select air to be directed (defrost, combo vent and defrost, etc). If they go bad, they will sit there and "hunt" around their set-point and make these little click noises that are very subtle. Didn't matter what the temperature of the engine, outside or inside was....thank god, I had a 100K warranty on the car cause it wasn't cheap. They replaced all of them on one trip.
JC

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No - engine temp seems to have no bearing on when/if this sound occurs, although I will say that I seem to hear it louder and more consistently when it is cold outside. Changing temp set points, or other settings on the climate control system doesn't seem to affect it.

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