Theory Of Operation
WARNING: This page is about a different car, the 2012 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The Evaporator Temperature Sensor resistance changes in conjunction to temperature. The sensor thermistor forms the lower half of a voltage divider and the upper half of the voltage divider is provided by a 9.09K pull up resistor to 5.0 volts.