Hi all I am new to the forum as only just got the A4 saloon 1.9tdi 130pd Since having it I can't get the rear demister to switch on.

When I push the switch on the centre console it lights up but then turns off as soon as I release it. I can hear a slight clicking noise coming from back of centre console if I listen carefully.

I have checked the fuse and it is fine but don't really know where to go from hear.

Are there any common faults on the unit I could test myself.
Any help would be much appreciated

Chris

Ps the engine temp won't get above 70c and getting about 42.6mpg with carefull driving mostly on B roads but have been in a bit of traffic (A bit low i think but hopefully because of over fuelling due to low temp of engine) I've ordered a thermostat so hope I've done right. Nearly went for coolant temp sensor but seems to steady and does drop slightly in temp when at speed so think cts is working.

Does this seem like the correct diagnosis to all you seasoned Audi owners.

This is all a bit more complex than my 1986 vw T3 haha