Car Heater Not Blowing Hot Air

If the car has an automatic control system, the possible problem is a bad ambient air sensor or a problem with the blend door.
An automatic temperature control system uses an on-board computer to maintain a constant passenger compartment temperature (as set by the driver). The computer is fed data from a sensor that measures ambient air temperature. Based on this data, a calculation is made by the computer to determine the appropriate blend door angle. The angle of the blend door essentially ...