Duct Sensor
WARNING: This page is about a different car, the 2002 Isuzu Axiom. However, it is still accessible from the selected car via links, so may be relevant.
The duct sensor is the sensor to detect temperature change of the side of evaporator blower coming by fresh recirculation of intake door or "on" "off" of compressor.
The temperature is converted to resistant rate.
And it works as thermostat to control to prevent freezing of evaporator.
This sensor is installed in the upper case of evaporator.