Temperature Sensor (Gauge): Testing and Inspection

1. Disconnect the YEL/GRN wire from the Engine Coolant Temperature (ECT) sending unit.
2. Using an ohmmeter, measure the change in resistance between the positive terminal and the engine (ground) with the engine cold and with the engine at operating temperature.
- If the temperature is 133°F (56°C) Then the resistance should be 137 Ohms.
- If the temperature is 185 - 212°F (85 - 100°C) Then the resistance should be 46 - 30 Ohms.
3. If the obtained readings are substantially different from the specifications above, replace the sending unit.