I have a strange problem that I will contact the dealership about but it is always useful to hear if anybody has had a similar problem. Very occasionally the seat will start to heat on its own without me pressing the control button to activate this function. Is there an automatic function that turns on the seat heater? I am unable to find such a function in the manual. I suspect a malfunction but would be interested to hear other opinion. 2004 645Ci. Magnificent car!