Today i put my A/C on in my truck, it was one click before HI, all of a sudden it just shut off. now the only speed that works is HI... any idea why this happened?

 

My GM truck did the same thing. Could only use high setting on fan. Turned out to be the blower motor. I think there is a resistor on the Fords. Or maybe your blower switch is bad.

 

resister is the problem.

located under the hood on heater box.

 

its a located just below and to the right of blower. All you will see is an harness plugged into it. Unplug harness and is held in by 1-2 screws. Under $20 at Ford (I paid $14 ) Will fix you right up .

 

Anyone know if this is the same issue I have in my 1990? Blower only runs when flipped all the way up to MAX.

 

nice, thanks for the info, i'll have to give it a try...

Virto, it sounds like yo have the exact same problem

 

It's gotta be the resistor I'd say.
Usually only one speed goes at a time though, but I'm betting its the resistor.
Each coil (three different gauges) in the resistor provides different amounts of 'resistance' based on the fan speed you select. High usually always works since no resistance is provide and the fan can run at max. (it's bad for the blower to always run on high)

I have issues with mice out here and they've trashed two of mine giving the same issues you describe. Someday I'm gonna screen off all inputs/outputs to the blower. (Irish spring soap and moth ***** don't deter mice by the way)

 

Anyone have a Ford part number?

 

I replaced my resistor and plug and it worked fine for 2 weeks, but now I'm back to square one,only the High speed is working again.
PLEASE HELP!!!!!
Does anyone have any suggestions??

 

Hmmm, worked for two weeks eh? Were you very careful with the new one when you installed it? Has 'something' gotten in there and put debris in the coils making them short out (again)? The coils are quite fragile and can't take too much banging around. It wouldn't take much to short those coils out either. Don't remove the tabs that lay across the top of each coil either.

Since it worked for two weeks, I think you're having resistor issues.

In case you haven't already, veryify the condition of all your wires leading to the resistor and from the resistor to the blower. Who knows, maybe something is shorting it out

Good luck bro

 

can some one show a picture of what the resistor is and where to find it under the hood? Thanks

 

Location is RH side of safety wall, on plenum.
Here is a link to the location.
http://i54.photobucket.com/albums/g9...orResistor.gif

Here is a photo of one.

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The 'coil side' will be inside the blower housing. The 'plug side' will be sticking out/screwed to the blower housing. The air from the blower helps keep the coils cool.

 

is it normal for all the speeds to go at once? do all speeds have there own coil or resistor?

 

Yes it happens that way.
Here is a link to a diagram.
http://i54.photobucket.com/albums/g9...lowermotor.gif
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