I have a 1986 TRX 350 and the cooling fan never comes on. What is the troubleshooting procedure for the oil sensor?

 

If you unplug the oil temp sensor wires and short them together the oil light & fan should start ..

 

Thanks again Honda Mech,

I'll check it out next time I go north.

BTW I used your wiring diagram and traced out the Neutral/reverse connections and found the previous owner had jumped them out. I cleaned and pinched the connections, and put them back the way they should be, and both indicator lights work as they should! I suspect the guy jumped out the neutral switch to get the starter to work when it really only needed to be cleaned up. I don't know why he jumped the reverse switch AND the oil sensor, perhaps he didn't really have a plan and just jumped things out until it started....

Thanks again for your help.