I’ve owned a 2009 Volvo V50 from new. From time to time the climate control, when set on automatic, suddenly changes so that it may be limited to a single zone, perhaps coupled with full fan. Other possible results are operation of windscreen heating or loss of air conditioning.

This misbehaviour can be rectified by pressing the appropriate control knob, but it’s proving to be a nuisance. I have been told by my local dealer that they have never come across this problem before. Have you any ideas?