I have a temp sensor that kicks on the electric fan. It is suppose to come on a 195*. I have ARP thread sealant on the threads.

Anyway the fan will not kick on. When I take the sensor out of the equation and run the fan when the igniton is on the fan works great.

What is the deal!

The switch is the kind with one terminal and the base is grounded such that when the switch closes the terminal is connected to ground? If so, grounding the terminal should turn the fan on. If this doesn't happen, then it's not wired right.

If that checks out okay, then with the switch above the closing temperature, try grounding the base. If this test works, then your thread sealer is interfering with the ground connection.

zeke67

I'll check that stuff out in the morning.

Its not the one wired kind. I believe its out of a 1990 Geo metro. It is a two wire deal.

Two wire kind. Are you running 12V to one terminal and the other terminal to the fan relay? If so, if you jump across the terminals the fan runs? If not, check your wiring. If so, it's in the switch. You could test the switch on the stove in a pan of water. Connect an Ohm meter or continuity tester and heat the switch. Monitor the temp with a candy thermometer.

That is correct. One is hot and one runs to the fan relay. Does it really matter which wire from the switch is connected to the 12 volts and the fan relay wire?

It doesn't matter.