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

Fig. 21 Checking coolant temperature sensor.:

1. Remove sensor from intake manifold, then immerse sensing portion of sensor in a suitable heating container, Fig. 21. Do not allow temperature sensing portion of sensor to directly touch heated portion of container. Ensure hot water is continually stirred and connector terminal is held approximately .12 inch above water, Fig. 21.
2. Insert a suitable thermometer into container, then connect an ohmmeter to sensor.
3. Ohmmeter should indicate the following values:
a. At 32°F, ohmmeter should indicate 5.9k ohms.
b. At 68°F, ohmmeter should indicate 2.5k ohms.
c. At 104°F, ohmmeter should indicate 1.1k ohms.
d. At 176°F, ohmmeter should indicate 0.3k ohms.
4. If resistance values are as specified, coolant temperature sensor is satisfactory. If resistance values are not as specified, replace sensor.
5. Apply a suitable sealant to threaded portion of sensor, then install and torque to 21 ft. lbs., then securely tighten harness connector