Diagnostic Aids
WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
The following conditions must be met in order for the ECM to engage the A/C compressor clutch:
- Battery voltage is between 9 - 18 volts
- Engine coolant temperature (ECT) is less than 123°C (253°F)
- Engine speed is less than 4, 760 RPM
- Engine speed is more than 600 RPM
- A/C high side pressure is between 2929 - 269 kPa (425 - 39 psi)
- Throttle position is less than 100 percent
- Ambient air temperature is greater than 3°C (38°F)
- The A/C compressor cycling switch pressure is between 124-388 kPa (18-49 psi)
- ECM does not detect excessive torque load
- ECM does not detect insufficient idle quality