I have a problem that is about to drive me up the wall ! with the ign key in the "on " position the fan works fine..if i start the engine the fan quits and will not come back on no matter what I do..turn the engine off and the fan works fine again.. this problem is erratic, sometimes everything works great...just spent a very hot day on the road last weekend and have got to figure this out...thanks for your help........dave

Usually the ignition switch will cause this. After starting the car, turn back on the switch a little and see if that helps. If so, replace the ignition switch and lock assy.

Climate Control
 

If your MB has an auxilary water pump, try disconnecting that. I had the same problem on my 88 190E. The aux. water pump was causing the control to shut down.

Kevin E. Ryan
Winona, MN