Blower Motor Resistor
WARNING: This page is about a different car, the 1995 Ford Aerostar. However, it is still accessible from the selected car via links, so may be relevant.
Blower motor resistor assembly consists of 3 resistors (providing 4 blower speeds) and a thermal limiter. Thermal limiter is located a specified distance from resistors. If temperature at thermal limiter reaches 250°F (121°C), circuit opens and blower motor becomes inoperative in all positions except HI. Thermal limiter is not serviceable. Entire resistor assembly must be replaced if thermal limiter is faulty.