Blower motor issues.

[Old Ford Blue]

Ok, 73 F-100, factory AC truck. First off, I only have 3 speeds, with the bottom position being off(I don't think thats how its supposed to work, but thats it) anyhow, if I run it on medium or high within about 30 seconds it trips the circuit breaker.

Any ideas??


Thanks guys,
Gabe

 

[Mil1ion]

Too much draw on the resistor.
Perhaps the blower motor needs lubrication ?

 

[Proeliator]

Simple, replace your current blower motor with this blower motor; problem solved

 

[Old Ford Blue]

THAT would be sweet....

Simple, replace your current blower motor with this blower motor; problem solved

I may need to lubricate the motor, is it a pain to pull? Also is it possible for a bunch of crap from the cowl vent to get stuffed into the hvac box causing the blower to work overly hard?


Gabe

 

[Proeliator]

All blower jokes aside; the blower motor is actually pretty easy to pull and or replace. And yes, if its intake gets plugged with crap it can cause the motor to work harder than it would otherwise.

 

[Old Ford Blue]

So I should be able to yank the motor, lube it, and clean any crap in there out all at the same time. Sweet.

Guess I know what I need to do

 

[TexasRho83]

Simple, replace your current blower motor with this blower motor; problem solved

lol! Dumba$$

 

[Old Ford Blue]

Allright, so I popped the cover off the squirrel cage area, and it was nice and clean there, and also the fan spins freely and without any noise from the motor. It did seem that if I cracked the cover then more air came thru the vents, so maybe there is a bunch of crap up in there elsewhere?

Its also gotten to where the only speed I can run it on is the medium low setting(the low setting does nothing, so maybe my switch is messed up?) So I guess the next question is where is the circuit breaker for the blower motor?

Thanks guys.

 

[TexasRho83]

Don't think there's a 'circuit breaker' per se... just a fuse in your fuse block underneath driver's side of the dash

 

[Old Ford Blue]

I'm pretty sure the blower motor is not fused, since it will cut off, then magically come back on after a min or so...

Maybe I'm wrong and the motor is over heating or something?

 

[TexasRho83]

On later model trucks, it's a relay issue...

Think you may have a short in the wiring? Maybe a wire's being pinched somewhere ...

 

[89frankenford]

im not too familiar with the Gen 6 trucks but what about a blower motor resistor pack???maybe the resistors are messed up??

 

[Mil1ion]

You;re looking for this little guy shown here

on this layout

 

[dakonthemountain]

What about the switch itself? If it is not working correctly on all speeds perhaps it is shorting out? Just a thought.
Dak

 

[Mil1ion]

That is possible but not probable

The resistor "takes all the heat" so to speak.

 

[Old Ford Blue]

Thanks for all the ideas guys, and Dennis, I believe you are the winner, but will that make the blower not do anything on low, and over heat the breaker on med-hi, and hi?

Charles, I don't think theres anyway its a pinched wire as it will do it sitting perfectly still.

Also, could be the switch, but each speed still "clicks" like it should, not like its all worn out and it just slides up and down.

So I need a blower resistor for a 73 F-100 with AC. Cool, BTW, are they a pain to swap out? In your diagram it looks easy to access, but I don't recall ever seeing it...


Thanks again! Gabe

 

[m78]

Good luck finding it

 

[Mil1ion]

What is an electrical resistor ?

Glad you asked..

It resists electricity which causes Motors to speed up with LESS resistance and motors to slow down with MORE resistance.
Unfortunately the Resistance wire gets HOT when resisting current flow eventually the resistance wire fatigues so much the motor you are trying to slow down,will burnout and become useless.

How many resistors on a Ford Blower motor for heat or A/C ? as many as there are reduced speeds for the motor operation.

A 3 spd switch will signify there are 2 resistors

Low speed = High resistance
Med speed = Medium resistance
High speed = NO resistance

Here is a pic of a heater ( NO A/C) resistor)

The resistor on an 78/79 Ford Truck with AC is located on the top of the plenum (AC Box) under the dash

 

[Old Ford Blue]

So I'm gonna ass-u-me that on a 73 with AC its about the same spot? Whats the easiest spot to access it from? the glove box maybe?

And I'm also gonna ass-u-me that I can grab one of these at most any parts store?

Thanks Dennis, I can't wait to get some ac circulating in there

 

[TexasRho83]

Go 2-60 A/C...no resistors needed. Ever!