B0424 on GMC: How to Diagnose & Fix
Temperature Control Right Feedback Circuit / Actuator Range/Performance
2 GMC models · 2 documented issues · $150-$900 repair
B0424 on GMC by model: symptoms, diagnosis and fix
Sierra owners across both GMT800 and GMT900 generations frequently report small electric HVAC actuators stripping internal gears or losing calibration. The result is a repetitive clicking or tapping noise from the dash, air stuck on defrost or floor, or one side blowing hot while the other blows cold. This is one of the most common non-drivetrain complaints on these trucks and is heavily documented in owner forums and repair databases.
Common Symptoms
- clicking behind dash
- air only blows from defrost
- temperature stuck hot or cold
- driver and passenger temperatures do not match
- mode changes do not respond
- recirculation door inoperative
How to Fix
Diagnosis is done by commanding HVAC modes and temperatures while listening for actuator chatter and verifying door movement with a scan tool or visual inspection where accessible. Repair involves replacing the failed mode, blend, or recirculation actuator and then performing HVAC recalibration by fuse pull or scan-tool procedure depending on year and system configuration.
Sources for this issue (1)
Owners frequently report clicking behind the dash, air stuck on defrost or floor, or one side blowing the wrong temperature due to failed HVAC actuators. On Yukon XL models with front and rear climate systems, the mode and blend door actuators can strip gears or lose calibration over time. This is distinct from compressor failure and is a common repair on aging GMT800 SUVs.
Common Symptoms
- clicking noise behind dash
- air only blows from defrost vents
- driver and passenger temperatures do not match
- stuck on hot or cold air
- rear HVAC airflow mode incorrect
How to Fix
Use the HVAC self-diagnostic procedure or a scan tool where available, then identify whether the failed unit is the mode, temperature, or recirculation actuator. Replace the faulty actuator, inspect the door for binding, and perform actuator recalibration by pulling HVAC fuses or using the proper relearn procedure. Access can range from easy under-dash work to more involved dash disassembly depending on actuator location.
Sources for this issue (1)
B0424 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does B0424 mean on a GMC?
B0424 stands for "Temperature Control Right Feedback Circuit / Actuator Range/Performance." This is a body/HVAC code indicating the climate control system detected a range or performance problem with the right-side (passenger) temperature blend-door actuator feedback circuit. The blend-door actuator is a small motor that positions a door to mix hot and cold air for the passenger side, and the module monitors a feedback signal to confirm the door reaches commanded positions. The computer saw the actuator failing to move correctly or the feedback signal falling outside the expected range. This is a comfort-related fault and does not affect drivability or safety. On GMC it is documented across 2 models: Sierra 1500, Yukon XL.
What are the most common causes of B0424?
The most common causes of B0424 are: Failed passenger-side blend-door temperature actuator motor, Stuck, broken, or binding blend door, Wiring or connector fault in the actuator feedback circuit, Corroded or loose actuator electrical connector, Faulty HVAC control module, Low or unstable system voltage affecting the actuator. The specific cause varies by vehicle.
How much does it cost to fix B0424 on a GMC?
Published repair estimates on GMC range from $150 to $900 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for B0424 on a different make?
View B0424 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.