Erratic Operation Of HVAC System

WARNING: This page is about a different car, the 2002 Dodge Intrepid, 2002 Chrysler Intrepid, 2002 Chrysler Concorde, and 2002 Chrysler 300M. However, it is still accessible from the selected car via links, so may be relevant.

Erratic operation of the HVAC systems include lack of cool air, lack of hot air, unrequested mode change (ATC only), no control of mode or temperature control or tapping blend door noise. These symptoms may be accompanied by the following DTCs:

Blend door feedback.
Blend door stall.
A/C control mode door input shorted to battery.
In car temperature sensor failure.
ATC message not received.
Mode door stall.

Check for the presence of DTCs with the DRBIII(R). If the symptoms and or DTCs listed above are present, preform the following repair procedure:

With the vehicle at room temperature 50-80°F (10-27°C), pull the M-1 fuse for five minutes to erase any DTCs.
Replace the fuse and start the vehicle to recalibrate the HVAC system.
Operate the vehicle and HVAC system to verify that symptoms and or DTCs are gone.
If tapping noise or blend stall/feedback DTCs re-occur, additional diagnosis will be required.