Coolant Temperature Sensor / Switch HVAC: Description and Operation

Coolant Temperature Sensor
The engine's coolant temperature sensor is connected to Integrated Central Electronics (ICE). ICE uses the coolant temperature to control the radiator fan and switch off the A/C compressor at high temperatures.

ICE sends the temperature signal to the main instrument display panel. The main instrument display panel uses this to control the temperature gauge and send the coolant temperature signal to the ACC control module. The ACC control module uses the coolant temperature as an input value to decide whether the cold starting mode of operation is applicable. If it is, air distribution and fan speed are adjusted as a function of the coolant temperature.

If no coolant temperature signal can be obtained, the ACC control module calculates a default value which on starting is 0 °C and gradually rises to 100 °C.