Whirring noise coming from dashboard

[nahugry]

I recently noticed this.
There is some type of whirring/whinning noise coming from the dashboard.
Kinda like actuator moving type of mechanical noise. It goes for a second and slows down for about a quarter of a second before going back on for another second or so. Repeating.
I tried playing with some buttons and I noticed that the noise stops when I turn the vent completely off.
Its actually pretty loud to a point where if you don't have any music on, it gets your attention; becoming annoyed after a while.
I'm not sure if this is normal, or I should take it to the dealer to have them check it out.
This is my 3rd bimmer, and I've never heard this noise before.

[Bart001]

Such a noise is normal upon shutting off the car. If you shut off the car and sit in it for a while, you'll hear something like that after a bit.

As far as I know, such noises are NOT normal if happening somewhat frequently while you are driving. I never heard that, while driving, for the 3+ years I've driven an E60.

There have been a few threads here about this noise -- a search might turn up some more info for you.

[nahugry]

I did the search and it seems that most of the thread are about rattling or creaking noise from the dash.
Mine sounds like sharp whooshing noise. I don't even know how to explain the sound, but it sounds like some type of fan going at super high speed or hydraulic lift going up and down type of noise. Whinning is the only term I can think of.
Again, it goes for about a second or so slowing down for about a quarter second then going again. It doesn't seem to stop at all unless I press the "Off" button on the vent control.

[MN2828]

If you have NAV, it could be the DVD reading.