Air Conditioning Evaporator Temperature (ACET) Sensor
WARNING: This page is about a different variant/trim than selected.
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 affects 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, improving defrost/demist performance, reduce A/C clutch cycling, etc.
A/C EVAPORATOR TEMPERATURE (ACET) SENSOR VOLTAGE AND RESISTANCE
| °C | °F | Volts | Resistance (K ohms) |
|---|---|---|---|
| 100 | 212 | 0.47 | 2.08 |
| 90 | 194 | 0.61 | 2.80 |
| 80 | 176 | 0.80 | 3.84 |
| 70 | 158 | 1.05 | 5.34 |
| 60 | 140 | 1.37 | 7.55 |
| 50 | 122 | 1.77 | 10.93 |
| 40 | 104 | 2.23 | 16.11 |
| 30 | 86 | 2.74 | 24.25 |
| 20 | 68 | 3.26 | 37.34 |
| 10 | 50 | 3.73 | 58.99 |
| 0 | 32 | 4.14 | 95.85 |
| -10 | 14 | 4.45 | 160.31 |
| -20 | -4 | 4.66 | 276.96 |
NOTE:
These values can vary 15 percent due to sensor and VREF variations. Voltage values were calculated for VREF = 5.0 volts.