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

Coolant Temperature Sensor (CTS):

Located behind the distributor, the Coolant Temperature Sensor (CTS) measures the temperature of the engine coolant. Like the air temperature sensor, the CTS is a thermistor. As coolant temperature lowers, resistance increases, as it rises, resistance decreases. By monitoring the voltage drop of the coolant temperature sensor, the ECM detects the engine coolant temperature and that affects most systems under the control of the ECM.