Just bought a 2000 500 Sportsman. I need to diagnose the fan thermostat to see if it is working properly. Owner before the one I bought it from had wired in a switch to turn it on with. Short of letting it run 'til it boils over, I have no idea how to troubleshoot it.

 

A thermostat is a simple switch... With the bike off and with an ohm meter, it should read open. If the thermostat is out of the bike, using a heat source, heat the thermostat to the temperature needed to kick the fan on and the ohm meter should read a short.


Hope this helps...

 

chances are the sensor is bad.