just repaired mine ,the eco light wouldn't go out so wouldn't fire up the fans or compressor , read on the net it need re-gasing as low pressure would stop it working so had it done but still no joy ,so booked it into a local specialists and he tested and found pressure switch faulty but couldn't locate it LOL, so i went on net and found it is located on the side of the air-con rad at the side of the passenger headlights , rang audi and they had one in stock @ £52.88 so got it and fitted it ,i have nice ice cold air-con now