HVAC Rear Temperature Blend Door Actuator Malfunction
What does B1320 mean?
The B1320 code means the vehicle's onboard diagnostic system has detected: HVAC Rear Temperature Blend Door Actuator Malfunction. This is a low severity code.
Common Symptoms
- Rear vents blow only hot or only cold air
- Rear temperature setting has no effect
- Clicking noise from rear HVAC unit
- Rear zone climate control not responding
- Front and rear temperature outputs do not match settings
Probable Causes (Ranked by Likelihood)
- Failed rear blend door actuator Very High
- Stripped rear actuator gears High
- Rear HVAC control panel malfunction Moderate
- Broken rear blend door pivot Low
Step-by-Step Diagnostic Procedure
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Test rear temperature controls through full range
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Scan HVAC module for rear blend door DTCs
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Listen for clicking from rear HVAC unit during temp change
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Command rear blend door actuator with scan tool
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Check voltage at rear actuator connector
Frequently Asked Questions
Is the rear blend door actuator the same part as the front?
Often no. While they may look similar, rear actuators are usually different part numbers because the HVAC housing and door sizes differ between front and rear units.
Can I replace the rear blend door actuator myself?
The rear actuator is often more accessible than front actuators since it does not require dashboard removal. It is typically behind a rear trim panel, making it a moderate DIY repair.
Why is the rear climate different from the front if they are set the same?
Each zone has its own blend door and actuator. If the rear actuator fails, the rear will be stuck at one temperature regardless of the setting, while the front operates normally.