Hello, have a new TT and the following problem: When the air conditioner is switched on (fan on high power; temperature less than 20 degrees) some loud noise sounds, which reminds of a trumpet. lasts 3 to 4 seconds. Then it is gone again. The car vibrates slightly (you should notice the pedals). Is to be heard in idle at the traffic light and when switching off. Swimming on, becomes louder and then quieter again, then away and then after a few seconds it comes again….was in the Workshop. The problem was probably new. Has someone ever experienced it here? Does someone know such a sound? Maybe it doesn’t come from the air conditioning. It only strikes that it is only there when the air conditioning is switched on. Otherwise you don’t hear anything…