Diagnostic Aids

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

The following conditions must be met in order to turn on the A/C compressor:

Battery voltage is between 9 - 18 V.
Engine coolant temperature is less than 124°C (255°F).
Engine speed is greater than 600 RPM.
Engine speed is less than 5 500 RPM.
A/C high side pressure is between 269 - 2 929 kPa (39 - 425 PSI).
Throttle position is less than 100%.
Evaporator temperature is greater than 3°C (38°F).
ECM does not detect excessive torque load.
ECM does not detect insufficient idle quality.
The ambient temperature sensor senses above 1°C (34°F).
Blower motor is ON.