Engine - Coolant Temperature Sensor/Switch: Testing and Inspection

1. Warm engine to normal operating temperature and run at idle.
2. Remove rubber boot from connector.
3. Turn ignition switch to ``On.''
4. Check voltage between terminal (LR) and ground. If voltage is not approximately .5 volts, check resistance of water thermo sensor and check wiring harness for open or short circuit.
5. Check resistance of water thermo sensor as follows:
a. Remove water thermo sensor.
b. Place sensor in water with thermometer and heat up water gradually.
c. Check resistance of sensor and replace if not within specifications. Resistance should be 14.6-17.8k ohms at (-)4°F, 2.21-2.69k ohms at 68°F and .29-.354k ohms at 176°F.