DTC B12A8-11: Duct Sensor Short (Low) - Passenger Vent: General Description
WARNING: This page is about a different car, the 2024 Kia Sorento. However, it is still accessible from the selected car via links, so may be relevant.
The duct sensor detects inlet air temperature. It is a negative type thermistor resistance will increase with lower temperature, and decreases with less temperature.