B0423: How to Diagnose & Fix — Air Temperature Control (Passenger/Right Side) Circuit Performance
5 vehicles · 2 makes · $60-$650 repair
How to diagnose and fix B0423: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
GMC Sierra 3500HD · 2007–2019
Sierra 3500HD owners report clicking/ticking behind the dash and inability to control cabin temperature due to HVAC blend door or mode door actuator failures. GM service bulletins and owner reports describe stripped actuator gears or actuator motor failures that can leave the truck stuck on hot, cold, defrost, or a single vent mode.
Common Symptoms
- Clicking/ticking from dash when starting truck or changing temp
- Stuck on hot or stuck on cold air
- Air only comes from defrost or only from vents
- Inconsistent temperature left-to-right (dual zone)
- HVAC settings change but airflow/temperature does not
How to Fix
Identify the failed actuator (temperature blend, mode, or recirculation) using HVAC actuator recalibration and scan tool data where available. Replace the specific actuator and perform HVAC recalibration procedure after installation. If doors bind, inspect HVAC case/door movement before installing a new actuator.
Sources for this issue (1)
GMC Terrain · 2010–2017
The HVAC blend/mode-door actuators fail as their internal plastic gears strip, producing a repetitive clicking or knocking sound from behind the dash and causing loss of temperature or airflow control. On dual-zone systems one side commonly blows hot while the other blows cold, or the system sticks on one temperature. A click/pop typically means a stripped gear requiring replacement.
Common Symptoms
- Repetitive clicking/knocking behind dash
- One side hot, other side cold
- Stuck on cold or hot air
- Temperature setting has no effect
- No airflow mode change
How to Fix
Replace the failed blend/mode-door actuator (OEM/ACDelco recommended to avoid repeat aftermarket failures) and recalibrate with a scan tool after installation. The temperature (blend) actuator is the most common failure; mode/recirc actuators can also fail.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- HVAC Blend/Mode Door Actuator (1st design, 5-pin connector) — 2010 through early-2013OEM25952814 (ACDelco 15-73981)Cross-refDorman 604-185, Four Seasons 73253, SKP SK604185$13–$56
GM used ONE common actuator in several positions in this HVAC case (temperature/blend, mode, and air-inlet/recirculation), so this single part number covers whichever one is clicking — the temperature/blend actuator is the most common fa…
- HVAC Blend/Mode Door Actuator (2nd design, 6-pin connector) — 2013 through 2017OEM22877649 (ACDelco 15-74254)Cross-refDorman 604-180, Four Seasons 73251, GPD 1712923$13–$40
Same one-part-fits-several-positions arrangement as the early design: temperature/blend, mode, and air-inlet/recirculation actuators in this case all use this number.
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Sources for this issue (1)
GMC Yukon · 2007–2014
The small electric blend-door actuators that control temperature and air-flow direction strip their internal plastic gears, producing a repetitive tapping/clicking noise from behind the radio or glovebox and causing the HVAC to blow the wrong temperature (e.g., stuck cold on the passenger side) or fail to change modes. It is one of the most common comfort complaints on the GMT900 Yukon and often affects more than one of the several actuators over the vehicle's life.
Common Symptoms
- Repetitive clicking/tapping behind the dash or glovebox
- One side blows hot while the other blows cold
- Air won't switch between vents/floor/defrost
- Temperature setting doesn't change actual output
How to Fix
Replace the failed actuator with a GM Original Equipment ACDelco unit - the passenger temperature actuator is ACDelco 15-72971 (GM 89018365 / 52402588; aftermarket cross Dorman 604-106). Before buying parts, pull the HVAC fuse for ~60 seconds to force a recalibration in case the fault is only a stuck cal. After replacement, reconnect the battery and let the system self-calibrate. OEM/ACDelco parts are strongly recommended because cheap aftermarket actuators have a high early-failure rate on this platform.
Sources for this issue (1)
Chevrolet Camaro · 2010–2015
Chevrolet Cruze · 2011–2019
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B0423 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 B0423 mean?
B0423 stands for "Air Temperature Control (Passenger/Right Side) Circuit Performance." B0423 is an HVAC (climate control) code indicating a problem with the right/passenger-side air temperature control circuit, typically the temperature blend-door actuator that mixes hot and cold air. The climate control module is not getting the expected feedback position from this actuator, so the cabin temperature on that side may not match the setting. This is a comfort/convenience fault, not a safety issue.
What are the most common causes of B0423?
The most common causes of B0423 are: Faulty passenger-side temperature blend-door actuator, Stuck or broken blend door, Open, shorted, or chafed actuator wiring, Corroded or loose actuator connector, Faulty HVAC control module, Poor ground to the actuator, Mechanical obstruction binding the blend door. The specific cause varies by vehicle.
How much does it cost to fix B0423?
Repair costs for B0423 range from $60 to $650, depending on the vehicle and root cause.
Which vehicles are affected by B0423?
Au7o has documented B0423 across 5 vehicle models from 2 manufacturers: Chevrolet, GMC.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.