Theory Of Operation

The HVAC Module uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the HVAC 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 Panel Duct Temperature Sensor monitors the air temperature of the air from the panel duct and supplies an input signal to the HVAC Module. The Panel Duct Temperature Sensor resistance value will change in response to the air temperature from the panel duct. The resistance value is electronically transferred to the HVAC Module using a sensor ground circuit and a 5-volt reference signal circuit. Normal operation of the sensor the resistive value decreases when the panel duct air temperature decreases and the sensor resistive value increases when panel duct temperature increases.