Hi - my father in law on a recent visit started complaining that the climate control on my 2000 Passat V6 wasn't cold enough and started to mess around with the controls (I was away on a business trip, so was unable to stop him) - The aircon stopped working and only blows hot (temperate) air now. Whilst there had been a slow leak in the refrigerant over the last year, I had only just had it refilled, and am certain that it has nothing to do with loss of refrigerant as he maintains. Now, when I start the car, the climate control display flashes all the icons - one in particular I noticed was "DIAGNOSE". Has anyone had any experience of this, and if so, what is the solution? I wonder if he had blown a fuse for the compressor (I am not a techie).
I hope I don't have to take it for a (expensive) check at the local garage.

Thanks for your help

I have the same car, and last year the climatronic was malfunctioning (it was 90 outside, but it kept reading -40). I brought it in to the dealer, and they found that the air duct sensor had shorted out. It was about a $200 repair.