Coolant Temperature Sensor / Switch HVAC: Testing and Inspection

Engine Coolant Temperature (ECT) Switch
INSPECTION




1. INSPECT No.1 SWITCH CONTINUITY
a. Using an ohmmeter, check that no continuity exists between the terminals when the coolant temperature is above 98 °C (208 °F).
If continuity exists, replace the switch.
b. Using an ohmmeter, check that continuity exists between the terminals when the coolant temperature is below 88 °C (190 °F).
If no continuity exists, replace the switch.




2. 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 93 °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 83 °C (181 °F).
If no continuity exists, replace the switch.