The electric fan switch, or thermal switch, can be checked by placing the element in a bucket of water using an ohmmeter. Heat the water to approximately 207°-216°F (97°-102°C) and connect the switch leads to an ohmmeter. The switch should have no continuity until the temperature reaches this level. Let the water cool off below 207°F (97°C) and the switch should lose continuity. If the switch has no continuity at any temperature, replace it.
REMOVAL & INSTALLATION
See Figure 1
The thermal switch is located on the top of the radiator, usually on the passenger side.
- Disconnect the negative battery cable.
- Drain and recycle the engine coolant.
- Unplug the electrical connector from the switch.
- Using a suitable size socket or wrench, loosen the switch.
- Remove the switch by hand.
- Install the switch into the radiator, and start the threads by hand.
- Tighten the switch into the radiator, but take care not to overtighten or you will break the switch or radiator.
- Plug the electrical connector in.
- Connect the negative battery cable.
- Refill the coolant and start the engine.
- Let the vehicle warm up and check the operation of the fan switch.
- Check the level of the coolant.