[alpine]

have an issue.... only the highest fan setting works on my 98 f150.

what would be the issue and best way to resolve...?

Looks like your thermal limiter is gone. Its located on the plenum behind the glove box.(at least it is on the 2000)

Here's an excerpt from the service manual:

Blower Motor Thermal Limiter

The heater blower motor switch resistor has the following features:

The assembly is located on the passenger side of the plenum assembly behind the glove compartment (06010).
Three resistance elements are mounted on the resistor board to provide four A/C blower motor speeds.
Depending on the heater blower motor switch position, series resistance is added or bypassed in the A/C blower motor circuit to decrease or increase A/C blower motor speed.
An overheating protective device (thermal limiter) will open the resistor coil circuit when the temperature reaches 121°C (250°F), interrupting the blower motor operation in all speeds except HI.
The thermal limiter cannot be reset and is not serviceable.

You'll have to replace the whole board.

 

[SKRWZ]

have an issue.... only the highest fan setting works on my 98 f150.

what would be the issue and best way to resolve...?

Yes it does most likely sound like the resistor go to the dealer tell the parts guy you need a blower motor resistor their only like 12- 17 bucks, then replace it and your fan should work, it's an easy job to fix the resistor is located on the heater box passenger side look for a wire plug on the heater box below the glove compartment and there it is I think ts two 7mm screws hold it in

 

[SKRWZ]

so is it the whole board i have to replace or just a simple resistor?

Its a small board about 2"x 4" it is called a blower motor resistor heres what it looks like just look for it on the under passenger side heater box below the glove box door

Here's what a blower motor resistor looks like also

 

[Viper238]

pull it out first..

My dad's one piece got rusted bad and it broke..
so i grabbed a piece of wire and solidered it back together.. works perfect..

i would drop it first..

shouldn't take more then 5mins to get it down..

on my dad's '01 Lairat there was 3 screws holding a cover plate.. I think all 7mm
then 2 screws - 8mm holding the resistor pack in place in the blower motor shrouding..

pull it out and look @ it first..

might not cost you anything..

 

[SKRWZ]

well did you get it fixed yet ?

 

[Viper238]

well did you get it fixed yet ?

No doubt eh..
just leaving us in the dark..
:icon_wink:

 

[SKRWZ]

Get on it man... you waiting for Easter or something?????? LOL:happy-102:

 

[SKRWZ]

My guess is that it's still the resistor, But if you want ill look it up on the ford manual see what that says