John
 

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.