My fan doesn't seem to kick on my 99 Scrambler. The radiotor gets hot so I assume that the pump is working. I have checked all connectors and they look good. The thermal switch on the radiator gets hot to the touch so it may be the that but I am not a mechanic, and don't know how to test to see if it is the fan motor or switch. I've read in other messages to trip the fan but I don't know how to do it. Need help.

 

To tell if it is the thermal switch just put a jumper across the plug going to the sensor, if fan starts is the sensor.

 

Yeah hes right but you still need to check the fan it self. If you jump a wire across the sensor and the fan don't run you may think the sensor is bad when in reallity the fan is shot. Check them both out.

 

The fan works when I trip it. I ended up putting a switch to manually control the fan and that seems to work out. I've had it on for a week or so and have been riding pretty hard through mud and water. Thanks for all the help.

 

If you are not going to replace the sensor and run the fan all the time, remember to turn it off before going through deep water.

 

I would replace the sensor, make sure it is working, and keep the switch as a back up.

 

There is a reason for the thermal switch on liquid cooled engines, one being for the engine to operate at the temperature range they designed it for. If the fan runs all the time, the engine cannot heat up to it's designed operating temperature nearly as fast, resulting in what some engineers claim to be "sludge buildup" in the oil system of the engine. Same thing goes for automobiles - the thermostat is there for more than just making the heater warmer faster in the winter.