Wirring noise when air-con is on

The sound is only present when the aircon is on, at any setting. It sounds like something rotating that needs oiling or is vibrating around it's axis... or a pump that is noisy.

I took it into (Croydon) Audi and they changed the unit with the fan in it for a new one (this isn't the fan that changes speed in the dash, it's the one under the bonnet).

I still get the noise... the guy there suggested it might be a pump or something else, but they're confused.

Any help as to what parts can be swapped out to get rid of the noise (which is only faint, and occures more when facing up-hill) I'd be very grateful... their workshop isn't busy, so I can get in quick with any work needed.

I'll try it with/without ECON on and let you know.

The noise only appears when the engine is running, and so can't be heard when you put your head under the hood as the engine noise is too loud outside the cabin. It seems to be coming from under the hood, rather than in the console, but noise can travel in a funny way so I can't be sure.

Any ideas?

thanks... I'll try the ECON switch and see what happens /ubbthreads/images/graemlins/smile.gif

switching ECON on makes the noise stop /ubbthreads/images/graemlins/smile.gif

I'll call my dealer now...

thanks... group hug? /ubbthreads/images/graemlins/wink.gif