Coolant Temperature Sensor/Switch (For Computer): Description and Operation

Engine Coolant Temperature (ECT) Sensor ('04-05 models)/Engine Coolant Temperature (ECT) Sensors 1 and 2 ('06-08 models)
ECT sensor ('04-05 models)/ECT sensor 1 and 2 ('06-08 models) is a temperature dependent resistor (thermistor). The resistance decreases as the engine coolant temperature increases.