Just bought a '95 C220 and within a month the heater control lights started flashing (when headlights off), the temperature wheels don't function and all I get is hot air. Holding the recirc button only makes its LED flash with the lights. I turn on the headlights and the heater lights go off, the recirc and the tempcontrols still do nothing. I suspect either a bad earth or bad positive connection causing a low voltage to the unit (considering that it goes off when lights go on) but don't know where to start looking.

Seen a few other threads from 2007 about this but no sensible solutions posted. It seems only UK cars have the straight heater fitted, as all the stuff I can find refers to AC units.

Its not too bad now with the cold weather, but in a couple of months it will be awful! Especially as I have a gremlin in my electric windows which means they don't work, I remove the motor and test it - it works ok, I refit it, the windows work for a week or so then stop again.........Joy!!!