My 2000 Mercedes S430 recently began overheating. Troubleshooting revealed that the coolant suction fan is not turning on. Placing a power probe on both of the cables to the coolant fan motor reveals ground on both ends.


I am not familiar with how the coolant fan system works on my particular car, but I do see that it is controlled by some sort of fan control unit. Unfortunately, I am not able to find wiring diagrams or fuse relay diagrams that really help me understand what is going on.


For any sake, I had no problems with this vehicle whatsoever until I decided to kick the transmission into "manual" shift mode and take over gears. After getting to a stop light I noticed the engine slightly "missing" at a complete stop and hesitating to take off, and after sitting the engine temperature rises dangerously and the "Coolant - Maintenance Needed" indicator came on.


The temperature is still doing this, but the engine "stutter" only occurs randomly and usually goes away if I turn off the car and start it again.


Has anyone had any like experiences? I was wondering if it was an electrical issue -- perhaps a bad or failing ground somewhere. Any help is appreciated. I'm not shy of diagrams or troubleshooting, but I hurt for time so replies may be few and far between!


Thanks!