I recently purchased a 96 A4 and I've noticed the climate control makes a somewhat strange, intermittent buzzing noise when it is on (auto or manual). I took it to a dealer who told me that this noise is normal, and that is due to some "doors" opening and closing within the system. Maybe this is true but I'm thinking the guy's nuts and that maybe I should check with a different dealer.

Your temp sensor is turning the compressor on and off, resulting in an intermittent "clicking" sound that seems to come from the left side of the dash...<p>Get your temp sensor replaced, this was a problem on my car too.<p>Cameron<br>