Ford F150 - Heat/Air Problem

On my 93 F150, The Blower motor will only work with the selector on full blast, anything before that, it will not work at all. The heat and air both work good on high, but its kind of annoying because i have to keep turning it on and off. Anyone had this problem? My first suspicion is the switch.

Sounds like your fan motor resistor block is gone. It is locted in the engine compartment on the heater housing.
regards
rikard

Definitely a burned-out resistor fuse. Replace the resistor.



While you have it out, inspect the evaporator fins. If they're dirty, pull the evaporator out (just take the cover off - you don't have to open the refrigerant system) and wash it out.