Circuit/System Testing

WARNING: This page is about a different car, the 2017 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, disconnect the harness connector at the Q46 A/C Compressor Solenoid Valve. Connect a test light between terminals 1 and 2 of the harness connector. Ignition ON.
Verify the test light turns on and off when commanding the Q46 A/C Compressor Solenoid Valve ON and OFF with the scan tool.
- If the test light does not turn ON and OFF
1. Ignition OFF, disconnect the X2 harness connector at the K33 HVAC Control Module, ignition ON.
2. Test for less than 1 V between ground and each control circuit terminal listed below:
  - terminal 10
  - terminal 11
  - If 1 V or greater, repair the short to voltage on the circuit.
  - If less than 1 V
3. Ignition OFF.
4. Test for infinite resistance between ground and each control circuit terminal listed below:
  - terminal 10
  - terminal 11
  - If less than infinite resistance, repair the short to ground on the circuit.
  - If infinite resistance
5. Test for less than 2 Ω in each of the control circuits end to end listed below:
  - Q46 A/C Compressor Solenoid Valve terminal 1 and K33 HVAC Control Module terminal 10
  - Q46 A/C Compressor Solenoid Valve terminal 2 and K33 HVAC Control Module terminal 11
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the K33 HVAC Control Module.
- If the test light turns ON and OFF
Test the Q46 A/C Compressor Solenoid Valve or replace the G1 A/C Compressor.