Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection

Engine Coolant Temperature (ECT) Switch Test:

NOTE: Bleed air from the cooling system after installing the engine coolant temperature (ECT) switch.

1. Remove ECT switch A from the thermostat housing and ECT switch B from the thermostat cover.
2. Suspend each ECT switch in a container of water or engine oil as shown.

NOTE: The illustration shows ECT switch A.

3. Heat the water or engine oil, and check its temperature with a thermometer.

Engine Coolant Temperature (ECT) Switch Test:

4. Check each ECT switch for continuity between the A and B terminals according to the table.