AJ Khan

Hi there I have C 200 Mercedes elegance auto year 1998 with 200000 km on clock but in top order the other day I spry and washed under the bonnet done it to lot of cars for 45 years like them clean on that night when it was a cold Melbourne night the radiator fan turned itself on full speed till the battery was flat next day I charged the battery drayed the engine bay with air pressure all the electric joints one night it was ok but today it did it again but by removing the fuse it stooped even called RACV he didn't know what to do went to my mechanic he didn't know please help me and tell me what it is and yes it happens when the car is cold and the keys are out, so confuse.

Torn65

Without looking at a wiring diagram generally the electric cooling fan only comes on with hot engine temperatures or air conditioning in operation on a hot day. You need to determine which circuit is turning on the fan. Make sure you blow any water out from the pressure switch on the receiver/drier assemble which is below the rear passengers headlight. It looks like a steel can with hoses attached. I would say water has got into a connector and its making the engine or a/c control unit think its hot. It is strange that this is happening while keys are out of ignition. If it happens again locate and remove the fuse which stops the fan and at least you will know which system is turning the fan on. Hope this helps.