Humidity Sensor
WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, and 2011 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
The humidity sensor is used by the HVAC module to optimize the Air Conditioning Compressor Module (ACCM) operation for reduced electrical system load while maintaining passenger comfort.
When the relative humidity inside the vehicle is low, passengers are comfortable at a higher air temperature. The ACCM can decrease the compressor rpm before the commanded temperature is reached to reduce compressor electrical load while maintaining passenger comfort.