Buzzing noise - REST fan on?

[Erfan]

When key is in position 2 I hear a buzzing noise that has gotten louder over the last few days. It does sound like the fan for the REST function on the climate control. The noise continues whenever the engine is switched on and only ceases about 5 seconds after the engine is switched off. Is there a fuse / relay just to deal with this?

I found one fuse but when pulled out it took out all of the climate functions.

The climate works fine other than this issue.

Thanks in advance

 

[whitenemesis]

REST function only operates with IGN off.

Could be the a/c thermo aspirator fan. Or the a/c booster fan, maybe some crud on the fan? Does the sound change with a/c fan speed?

 

[Erfan]

Thanks:

- The sound does not change with fan speed.
- I cited the REST example as that is the same noise I can hear when the IGN is in pos. 2 - (Obviously as you state IGN off to get REST to work)

- Where is the fan (to check for crud) / thermo aspirator / booster fan? Do the last 2 have individual fuses?

From the engine bay it sounds like it's coming from the bottom/rear manifold area. and from inside like its coming from glovebox area

 

[Erfan]

I will check the fan. Is there just one under the glovebox or is there one somewhere else also?

 

[Erfan]

Solved! Buzzing noise

Turns out it was the little internal air temperature fan sensor located in the dome lights (above rear view mirror).

For reference the part number is:

A140 830 00 08 - £78 (incl. vat) from dealer! (though I read elsewhere this was for a pack of 5?).

I have cleaned and oiled for now and the noise has gone. We'll see if it comes back.

Also if I wanted to disconnect the auto dimming mirror do I just unplug the aqua coloured plug?

Thanks