Radiator Cooling Fan Temperature Sensor / Switch: Testing and Inspection

1. Remove thermo switch/sensor as outlined under Cooling Fan Motor Switch.
2. Connect suitable ohmmeter across switch terminals, then immerse lower part of switch in water. Ohmmeter should indicate an open circuit.
3. Heat water until temperature reaches approximately 212°F. Switch contacts should close and the ohmmeter should indicate continuity.
4. If switch does not operate properly, replace it.