Coolant Temperature Sensor / Switch HVAC: Testing and Inspection

ENGINE COOLANT TEMPERATURE (ECT) SWITCH

INSPECTION

1. DRAIN ENGINE COOLANT
2. REMOVE ECT SWITCHES




3. INSPECT NO.1 ECT SWITCH
a. Using an ohmmeter, check that there is no continuity between the switch terminals when the coolant temperature is above 98 °C (208 °F).
If there is continuity, replace the switch.

b. Using an ohmmeter, check that there is continuity between the switch terminals when the coolant temperature is below 88 °C (190 °F).
If there is no continuity, replace the switch.




4. INSPECT NO.2 ECT SWITCH
a. Using an ohmmeter, check that there is continuity between the switch terminals when the coolant temperature is above 94 °C (201 °F).
b. Using an ohmmeter, check that there is no continuity between the switch terminals when the coolant temperature is below 83 °C (181 °F).
If continuity is not as specified, replace the switch.

5. REINSTALL ECT SWITCHES
6. REFILL WITH ENGINE COOLANT