Thermal Limiter
WARNING: This page is about a different car, the 1995 Ford RV Cutaway, 1995 Ford Econoline, 1995 Ford Cutaway, and 1995 Ford Club Wagon. However, it is still accessible from the selected car via links, so may be relevant.
Thermal limiter, part of blower motor resistor, is located to right of blower motor on evaporator housing. If thermal limiter is blown, fan only operates at HI speed. To check for blown thermal limiter, ensure continuity exists on all blower resistor terminals. If continuity does not exist, replace blower motor resistor.