Theory Of Operation

WARNING: This page is about a different car, the 2014 Dodge Journey. However, it is still accessible from the selected car via links, so may be relevant.

The HVAC A/C Heater Module uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the A/C Heater Module to assure that they are in range. An active Diagnostic trouble Code (DTC) indicates that a sensor is out of range. A stored DTC indicates that the sensor was out of range but is currently within range.

The In-Car Temperature Sensor uses a temperature thermistor which changes in its resistive value with differences in air temperature of the interior cabin. Air is drawn from the passenger compartment by an aspirator (small fan driven by a 12-volt electric motor) which circulates air over the temperature thermistor. The A/C Heater Module receives the resistance value over a two wire circuit that is used to calculate the temperature and make any adjustments to maintain the optimum passenger compartment comfort. The In-Car Temperature Sensor cannot be adjusted or repaired and must be replaced if inoperative or damaged.