Radiator Cooling Fan Temperature Sensor / Switch: Testing and Inspection

Fig. 43 Testing Thermo Sensor:

1. Remove thermo sensor from radiator.
2. Submerge sensor end of thermo sensor in water as shown.
3. Connect ohmmeter across thermo sensor terminal and casing, then heat water.
4. When water temperature reaches approximately 185°F, the thermo sensor contacts should close and continuity should exist between sensor terminals.
5. Allow water to cool with thermo sensor still submerged. When water temperature drops to approximately 172°F, the thermo sensor contacts should open and continuity should not exist between sensor terminals.