Trouble Shooting & Testing Coolant Temperature Sensor

Coolant temperature sensor is located in lower corner of radiator. Drain cooling system and remove coolant temperature sensor. Place coolant temperature sensor in water up to the mounting threads. Heat water to 185°F (85°C) and check for continuity. Continuity should exist. Reduce water temperature to less than 172°F (78°C). No continuity should exist. Replace sensor if defective.