Engine - Coolant Temperature Sensor/Switch: Testing and Inspection

1. Run engine until normal operating temperature is reached.
2. Remove rubber boot from sensor electrical connector.
3. Turn ignition switch to the On position, then measure voltage between connector terminal and ground.
4. If voltmeter does not indicate approximately .5 volt, check resistance of thermo sensor as follows:
a. Remove sensor and heat is a suitable container of water.
b. Measure resistance across sensor terminals using a suitable ohmmeter.
c. Resistance should measure 2.21---2.69K ohms at 68°F and .290---.354K ohms at 176°F.
d. If resistance measurements are not within specifications, replace the sensor.