Auxilary heater fan ?

[philip600]

Hi everyone,

I wondered if anyone can help with a strange problem on my X5.
It's a UK spec 3.0d with the auxilary heater fitted.
Recently when I lock or unlock the car or even just open the door if it's been stood on the drive there is an intermittent fan noise that stops & starts quite a few times before eventually shutting down.
The noise is coming from the auxilary heater fan, confirmed by taking the air intake hose from it's mounting in the inner wing & putting my hand over the end, I can feel air being sucked in in time with the fan going on & off.
It's as if the heater is trying to fire up but I can't understand why it would even try when the temperature is in the 20's
I did a search on here but couldn't find anything but seem to remember a post on X5driver about an X5 making a ''breathing'' sound, this is what it sounds like. My Wife thinks the car is alive

Any help would be appreciated.
Kind Regards, Phil.