Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit/System Testing
- Ignition ON
- Verify the scan tool Blower Motor Switch parameter changes when rotating the blower switch through each speed position
- Verify the blower motor operates properly with the blower motor switch in each speed position
- Verify the scan tool parameters listed below change when pressing the appropriate switch
- Left Temperature Knob Position
- Air Recirculation Mode Switch
- Bi-Level Switch
If any parameter does not change
Replace the A26 HVAC controls
If all parameters change
- Verify the HVAC doors listed below move when pressing the appropriate switch
- Temperature
- Bi-Level 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 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
- Verify the A/C High Side Pressure Sensor parameter is between 269-2929 kPa (39-425 PSI).
- Engine ON, A/C system ON
- Verify cool air flows from the ducts with the temperature control in the coldest position
- Observe the Q2 A/C Compressor Clutch
- Verify the Q2 A/C Compressor Clutch is engaged
- If the Q2 A/C Compressor Clutch is not engaged Refer to DTC P0645, P0646, or P0647
- 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 not cool
If the air is cool
- Verify warm air flows from the ducts with the temperature control in the warmest position
- All OK.
If the parameter does not change for each speed position
Replace the A26 HVAC controls
If the parameter changes for each speed position
If the blower motor does not operate in each speed position
Refer to DTC B0193
If the blower motor operates properly in each speed position
If the reading is not within 10%
Refer to DTC P0532 or P0533
If the reading is within 10%
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)
If the air is not warm
Refer to HEATING PERFORMANCE DIAGNOSTIC
If the air is warm
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.