Engine - Coolant Temperature Sensor/Switch: Description and Operation

Task
Detecting the coolant temperature and supplying information to the engine control module

Design
Plastic housing with an NTC resistor, 2-pin, angled plug connection.
Contact assignment at connector:
Contacts 1 and 2 engine control module.
Inserted into hole and sealed with O-ring.
Attached by means of spring clasp.

Function
The NTC resistor integrated in the coolant temperature sensor alters its electrical resistance in line with the coolant temperature. NTC means Negative Temperature Coefficient, i.e, the electrical resistance becomes less as the temperature rises.

Example:
coolant temperature resistance
20 °C 3100 ohm ± 5%
80 °C 315 ohm ± 5%