Engine - Coolant Temperature Sensor/Switch: Testing and Inspection

With an ohm meter check resistance of sensor at specified temperatures.
2.1 - 2.9k ohms 20° C (68° F)
0.68 - 1.0k ohms 50° C (122° F)
0.30 - .33k ohms 80° C (176° F)
Replace sensor if it fails the above test.