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

Fig. 4 Water temperature sensor:

The water temperature sensor, incorporated into the thermostat housing, Fig. 4, monitors change in cooling water temperature and transmits a signal for the fuel enrichment to change the pulse duration during warm-up. The temperature sensing unit employs a thermistor which is very sensitive in the low temperature range. The electrical resistance of the thermistor decreases in response to the rise in water temperature.