So today I was out in the CLK with the heater on and nice and warm, suddenly and without me touching the heater controls, it started blowing cold on both sides of the car. Tried everything I could think of but no joy temp gauge normal. Recent new thermostat and auxilliary water pump fitted, main water pump done two years back. The blower fan seems to be not working on the lower settings ? Coolant level is fine, weather permitting I will have another look tomorrow but any help would be much appreciated.
