Engine - Coolant Temperature Sensor/Switch: Testing and Inspection

With an ohm meter check resistance of sensor at specified temperatures.
2.3 - 2.7k ohms 20° C (68° F)
0.77 - 0.87k ohms 50° C (122° F)
0.30 - 0.33k ohms 80° C (176° F)
Replace sensor if it fails the above test.