Circuit/System Verification

NOTE: Check for bulletins before proceeding.

Ignition ON.
Verify every applicable scan tool Switch parameter changes when pressing the appropriate switch on the A26 HVAC Controls.
- If any parameter does not change
  Replace the A26 HVAC Controls.
- If all parameters change
Verify the blower motor operates properly with the blower motor switch in each speed position.
- If the blower motor does not operate properly in each speed position
  Refer to DTC B0193 .
- If the blower motor operates properly in each speed position
Verify the HVAC doors listed below move when pressing the appropriate switch.
- Temperature
- Mode
- Recirculation
- If any HVAC door does not move
  Refer to DTC B0223, B0233, B023A or B0408 .
- If all HVAC doors move
Install the J43600 ACR Air Conditioning Service Center.
Verify the high side pressure reading on the Air Conditioning Service Center is within 10% of the scan tool A/C High Side Pressure Sensor parameter.
- If the reading is not within 10%
  Refer to DTC P0532 or P0533: Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit .
- If the reading is within 10%
Verify the A/C High Side Pressure Sensor parameter is between 269-2929 kPa (39-425 PSI).
- If the reading is not between 269-2929 kPa (39-425 PSI)
  Refer to Air Conditioning (A/C) System Performance Test
- If the reading is between 269-2929 kPa (39-425 PSI)
Verify the scan tool A/C Evaporator Temperature Sensor parameter listed is within 10% of ambient temperature.
- If not within 10% of ambient temperature
  Refer to DTC B3933 .
- If within 10% of ambient temperature
Engine ON, A/C system ON.
Verify cool air flows from the ducts with the temperature control in the coldest position.
- If the air is not cool
1. Verify the Q2 A/C Compressor Clutch is engaged.
  - If the Q2 A/C Compressor Clutch is not engaged, refer to Air Conditioning Compressor Malfunction .
  - If the Q2 A/C Compressor Clutch is engaged, refer to Air Conditioning (A/C) System Performance Test and DTC B393B .
- If the air is cool
Verify warm air flows from the ducts with the temperature control in the warmest position.
- If the air is not warm
  Refer to Heating Performance Diagnostic .
- If the air is warm
Verify the vehicle is not equipped with an E40 Electrical Auxiliary Heater.
- If the vehicle is equipped with an E40 Electrical Auxiliary Heater
1. Verify the E40 Electrical Auxiliary Heater turns On and Off when commanded within the conditions for proper operation listed in Manual HVAC Description and Operation .
  - If the E40 Electrical Auxiliary Heater does not turn On and Off when commanded within the conditions for proper operation
    Refer to DTC B048D or B048E .
  - If the E40 Electrical Auxiliary Heater turns On and Off when commanded within the conditions for proper operation
2. All OK.
- If the vehicle is not equipped with an E40 Electrical Auxiliary Heater
All OK.