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Coolant Temperature Sensor / Switch HVAC: Testing and Inspection

INSPECTION

1. DRAIN ENGINE COOLANT FROM RADIATOR

HINT: It is not necessary to drain out all the coolant.




2. REMOVE ECT SWITCH




3. INSPECT No.1 SWITCH CONTINUITY
a. Using an ohmmeter, check that no continuity exists between the terminals when the coolant temperature is above 90°C (194 °F).
If continuity exists, replace the switch.
b. Using an ohmmeter, check that continuity exists between the terminals when the coolant temperature is below 95°C (203 °F).
If no continuity exists, replace the switch.




4. INSPECT No.2 SWITCH CONTINUITY
a. Using an ohmmeter, check that no continuity exists between the terminal and switch body when the coolant temperature is above 95°C (199°F).
If continuity exists, replace the switch.
b. Using an ohmmeter, check that continuity exists between the terminals when the coolant temperature is below 90°C (194°F).
If no continuity exists, replace the switch.




5. INSTALL ECT SWITCH
6. FILL WITH ENGINE COOLANT