The jeep hasn't been used for a while, and the blower motor fuse kept blowing. So I took the motor out, and it seemed stuck (rust?) and wouldn't turn. I took a wrench and turned it to get it unstuck. I sprayed wd-40 on the inside, and put it back in the car, and it worked. a couple hours later when i start the car again, the motor wont do anything, the fuse is not blown, and i used a multimeter, and it was getting power.

Is there anything I can do to fix it, or do I have to buy a whole new motor?

 

New motors are cheap. Yours is probably toast.

 

I don't trust the fact you blowing fuses
So you have power you say.
Check ground
Check resistance in pathways

If they all check out and your motor is still not doing anything, it's more likely the component itself.

 

Wiring, switch, motor and resistor, not much to it.

 

People don't realize WD40 is not a lubricant because it evaporates after a short while. I'd say your motor at the very least needs oil on the shaft or to be replaced. Word to the wise. You're only going to find a Chinese motor and they come with 2 black wires. They are permanent magnet motors and can run in either direction by changing polarity. Make sure it runs in the same direction as the old one. Squirrel cage fans are very hard to tell which direction they are supposed to run in and if wired in reverse don't move much air.

IDK if your 91 is wired the same as the newer models, but they are wired with 12v directly to the motor and the resistor and speed switch is the ground path. Different speeds are created by using different taps off the resistor to reduce voltage.

 

If it's been rusted/seized, it's time for a replacement.

 

I've had a siezed one set on fire on a bench after freeing up. Since then I would never trust a fan, especially high current, that has had a bit of lubricant spray on it to free it up.

Even if the fan spins and doesn't blow a fuse, it's highly likely to be drawing extra current than normal operation which is only worse for our already under-rated circuits.

 

Pay attention to Sparky^^^ here!!

 

Change the motor. Went thru three resistors in my '94 before putting in a new motor (old one "seemed" fine). That solved the issue. About to do the same to my new '98.

 

Here's what you can end up with if you ignore this issue and don't replace that motor.