Fan switch on 99 f-53 chassis

Hank MI wrote:
Not sure on the Ford chassis but the problem you describe is usually the resistor module.

X 3

Not sure on the Ford chassis but the problem you describe is usually the resistor module. I know it's a common failure item on some Chevy vehicles.

Many system have a resistor like this in the heater housing. Many are located under the dash passengers side. It is possible that some of the resistors has burnt out. They get moisture on them, rust and break.
Fan resistor
It may or may not be one from Ford.

Mine's the same way. I've been told that there's a separate fuse for the lower fan speeds. I've also been told there's a resistor panel mounted somewhere on or near the blower that is switched in as needed for the lower speeds. I haven't taken the time to pursue either of those . . . but it seems likely the problem isn't in the actual switch itself.

My manual shows a 15amp "blower relay" fuse in the under-dash fuse panel and a 40amp "blower motor feed" in the main fuse & relay panel in the engine compartment.

Please let us know what you find - I could use the info.

al