The Explorer is built with a Blend Door to control the heater and AC function. The blend door controls air flowing through AC evaporator and diverts it into the vent system or through the heater coil, or any combination in between. The doors are controlled by a DC motor. The issue with the design is that the system has to calibrate itself and find the end points of movement before the computer can understand the two closed positions and regulate the temperature. The motor is geared to move the doors slowly and with a good amount of force. The door has to withstand the force of stopping the motor, and like bending a coat hanger back and forth, will eventually break. Another reported fail symptom is a clicking sound coming from behind the HVAC system. On this model, this is usually an indication of a stripped gear in the motor. Again, replacing the motor is a temporary fix without a properly aligned blend door. The late model Explorer/Mountaineer is a complex system with significant flaws in the design and no provisions for simple access and repair. The fix is not easy, but we can resolve the issues.
Thursday, December 16th, 2010 AT 9:45 AM