Evaporator Temperature Sensor / Switch: Description and Operation

AIR CONDITIONING EVAPORATOR TEMPERATURE (ACET) SENSOR

A/C Evaporator Temperature (ACET) Sensor Voltage And Resistance:

The ACET sensor measures the evaporator air discharge temperature. The ACET sensor is a thermistor device in which resistance changes with temperature. The electrical resistance of a thermistor decreases as the temperature increases, and the resistance increases as the temperature decreases. The PCM sources a low current 5 volts on the ACET circuit. With SIG RTN also connected to the ACET sensor, the varying resistance changes the voltage drop across the sensor terminals. As A/C evaporator air temperature changes, the varying resistance of the ACET sensor changes the voltage the PCM detects.

The ACET sensor is used to more accurately control A/C clutch cycling, improve defrost/demist performance, and reduce A/C clutch cycling.

NOTE: These values can vary 15% due to sensor and VREF variations. Voltage values were calculated for VREF equals 5.0 volts.