We don't have the Fiesta here but most of them the heat is controlled by a blend door that regulates heated air flow. It is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.
Thursday, August 18th, 2011 AT 6:06 PM