B0147 is a GM/Chevrolet manufacturer-specific body/HVAC trouble code indicating a low electrical condition in the rear air-flow position command #3 circuit. It is associated with the rear or auxiliary HVAC actuator on applicable vehicles.
What Does B0147 Mean?
B0147 means Air Flow Position Command #3 (Rear) Circuit Low. The HVAC control system detects that the electrical signal or control circuit for the rear air-flow position actuator is lower than the expected operating range.
Code Type
Common Causes
- Short to ground in the actuator control circuit
- Faulty rear HVAC mode actuator
- Damaged or corroded actuator connector
- Damaged wiring
- Low or missing actuator control voltage
- Internal actuator motor failure
- Stuck rear HVAC air door
- HVAC control module fault
- Actuator calibration problem
Symptoms of B0147
- Rear airflow remains in one position
- Rear vents do not change when the HVAC mode is selected
- Rear HVAC mode operates incorrectly
- Clicking or abnormal actuator noise
- Airflow is directed to the wrong rear vents
- Rear HVAC may operate in a default position
- B0147 remains stored in the HVAC/RSA module
Is B0147 Serious?
B0147 is usually not an engine or transmission problem. It mainly affects rear HVAC airflow control. If the affected system also controls defrost airflow, the problem should be repaired because visibility can become a safety concern.
Can I Drive With B0147?
Usually yes if the fault only affects the rear HVAC system and the vehicle drives normally. Repair the problem if it affects windshield defrost operation or visibility.
Component Responsible
The component most commonly associated with B0147 is the rear/auxiliary HVAC air-flow position actuator.
On applicable GM systems, the actuator contains a motor and position-feedback circuitry. The HVAC module controls the actuator through dedicated circuits to move the rear air-distribution door.
Component Location
The actuator is mounted on the rear or auxiliary HVAC housing. Its exact location varies according to the GM/Chevrolet model, year, and HVAC configuration.
Some vehicles place the rear HVAC actuator behind interior or cargo-area trim close to the auxiliary HVAC assembly.
Check the Fuse
Check the HVAC/RSA-related fuses using the wiring diagram for the exact vehicle. Fuse numbers and circuit assignments vary between GM models and years.
If the fuse is good, continue testing the actuator wiring, connector, power, ground, control circuits, and actuator operation.
How to Diagnose B0147
- Use an enhanced scan tool capable of accessing the Rear HVAC/RSA module.
- Record B0147 and any companion HVAC codes.
- Command different rear airflow modes.
- Observe the actuator command and actual position.
- Inspect the actuator connector for corrosion, loose terminals, or damage.
- Inspect the wiring for shorts to ground or damaged insulation.
- Check the actuator control circuit for an abnormally low voltage condition.
- Check the actuator and rear air door for mechanical binding.
- Test the actuator according to the vehicle-specific GM service procedure.
- Perform actuator calibration after repair when required.
Live Data and Technical Diagnosis
A capable scan tool may display the commanded rear airflow position and actual actuator position or feedback value.
HVAC Command → Control Circuit → Rear Actuator → Air-Door Movement → Position Feedback → HVAC Module
Because B0147 indicates a low circuit condition, pay particular attention to a control wire shorted to ground, a damaged actuator, or a wiring fault pulling the circuit voltage down.
Do not use one universal voltage or resistance specification for every GM vehicle. Exact test values depend on the model, HVAC system, and actuator design.
How to Fix B0147
- Repair a shorted or damaged actuator control wire.
- Repair loose or corroded connector terminals.
- Restore the correct actuator power and control circuits.
- Replace a failed rear HVAC actuator.
- Repair a mechanically stuck air-distribution door.
- Perform actuator calibration or relearn when required.
- Clear the DTC and verify correct rear airflow operation.
Repair Cost for B0147
$50–$150
$100–$350
$100–$300
$200–$650
Actual cost depends on the GM/Chevrolet model, actuator accessibility, parts prices, and labor rates.
Common Repair Mistakes
- Replacing the HVAC module before testing the circuit.
- Replacing the actuator without checking for a short to ground.
- Ignoring damaged connector terminals.
- Skipping actuator calibration.
- Using an engine-only scanner that cannot access the HVAC module.
- Assuming B0147 is caused by an A/C refrigerant problem.
Related B0147 Codes
Air Flow Position Command #3 Rear Circuit Malfunction
Air Flow Position Command #3 Rear Range/Performance
Air Flow Position Command #3 Rear Circuit High
Air Flow Position Command #3 Rear Circuit Open
Air Flow Position Feedback #3 Rear Circuit Malfunction
Air Flow Position Feedback #3 Rear Range/Performance
Air Flow Position Feedback #3 Rear Circuit Low
Air Flow Position Feedback #3 Rear Circuit High
Air Flow Position Feedback #3 Rear Circuit Open
FAQ
What does B0147 mean?
B0147 means Air Flow Position Command #3 (Rear) Circuit Low. It indicates a low electrical condition in the rear HVAC air-flow position command circuit on applicable GM/Chevrolet vehicles.
Does B0147 mean the actuator is bad?
Not necessarily. A failed actuator is possible, but the wiring and connector should be checked for a short to ground or another low-voltage condition before replacing the actuator.
Can B0147 affect engine performance?
No. B0147 normally concerns the HVAC system and does not directly affect engine or transmission operation.
Can I drive with B0147?
Yes, in most cases if the problem is limited to rear HVAC airflow. Repair the fault if it affects defrost performance or visibility.