Circuit/System Testing

DTC B023A

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the components listed below. It may take up to 2 min for all vehicle systems to power down.
   • M4 Air Inlet Door Actuator
   • M37 Mode Door Actuator
   • M46 Air Recirculation Door Actuator
   • M6L Air Temperature Door Actuator - Left
   • M6R Air Temperature Door Actuator - Right
   • M37B Mode Door Actuator - Auxiliary
   • M6B Air Temperature Door Actuator - Auxiliary
2. Disconnect the X3 and X4 harness connectors at the K33 HVAC Control Module.
3. Test for infinite resistance between the K33 HVAC Control Module 12 V reference circuit terminal 15 X3 and ground.
   • If less than infinite resistance 

     Repair the short to ground on the circuit.

   • If infinite resistance 
4. Ignition ON.
5. Test for less than 1 V between the K33 HVAC Control Module 12 V reference circuit terminal 15 X3 and ground.
   • If 1 V or greater 

     Repair the short to voltage on the circuit.

   • If less than 1 V 
6. Connect the X3 and X4 harness connectors at the K33 HVAC Control Module, ignition ON.
7. Clear all DTCs.
8. Verify DTC B023A is not set.
   • If the DTC is set. 

     Replace the K33 HVAC Control Module.

   • If the DTC is not set. 
9. Verify DTC B023A does not set after connecting each of the components listed below one at a time and operating them through their full range.
   • M4 Air Inlet Door Actuator
   • M37 Mode Door Actuator
   • M46 Air Recirculation Door Actuator
   • M6L Air Temperature Door Actuator - Left
   • M6R Air Temperature Door Actuator - Right
   • M37B Mode Door Actuator - Auxiliary
   • M6B Air Temperature Door Actuator - Auxiliary
   • If the DTC sets 

     Replace the component that was connected immediately before the DTC set.

   • If the DTC does not set 
10. All OK.

DTC B0223, B022A, B0233, B0408, B0418, B0428 or B3531

1. Ignition OFF, disconnect the harness connector at the appropriate door actuator, ignition ON.
2. Verify a test lamp flashes when connected between the 12 V reference circuit terminal 2 and ground.
   • If the test lamp does not flash 
   1. Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module.
   2. Test for less than 2 Ω in the 12 V control circuit end to end.
      • 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 lamp flashes 
3. Connect a test lamp between each control circuit listed below and B+.
   • Control Circuit - terminal 1
   • Control Circuit - terminal 3
   • Control Circuit - terminal 4
   • Control Circuit - terminal 6
4. Command the appropriate door actuator in both directions.
5. Verify the test lamp turns ON and then OFF during at least one of the directional commands.
   • If the test lamp is always ON 
   1. Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module.
   2. Test for infinite resistance between the control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K33 HVAC Control Module.
   • If the test lamp is always OFF 
   1. Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
   2. Test for less than 1 V between the control circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
   3. Ignition OFF
   4. Test for less than 2 Ω in the control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance is the circuit.
      • If less than 2 Ω, replace the K33 HVAC Control Module.
   • If the test lamp turns ON and then OFF 
6. Test or replace the door actuator.