On a recent long distance trip in my XC60 I experienced the following strange behaviour from the aircon which was switched on at the time: it suddenly started to blow hot air (like burning hot air, as if the setting was on maximum heat) out of the driver's side vent - the passenger side vent still blew cold air. This lasted many minutes, until I pulled the car off in a safe spot and turned off the engine. After about 2 minutes I started the car and drove off, and the hot air kept on blowing for another 3 or 4 minutes and then it started to blow cold air again.

Any ideas?