I'm trying to diagnose a problem with my blower motor. It's not moving at all but it has power to it. I removed it and tried to run it straight off the battery but get just a small amount of movement likes it's trying to spin but it doesn't even make a quarter turn.

I understand the fan should be fully powered but the resistor works through the ground to cut down the speed.

I'm assuming with the fan wired straight to the battery, it should spin fast like it is on high. Can anybody confirm if this is correct or not?

Thanks

 

If the resistor is good and all related wiring, I'd say the motor is bad.

 

Yep, blower gets 12 volts, and then speed is controlled by assorted resistors in the ground path. (which you select with the switch.) If the motor doesn't wanna turn when directly powered (and a GOOD GROUND), replace the motor.

 

Thanks!

It was the motor. For future reference, if you connect the motor straight to the battery, it should run full speed. My old motor barely moved when I did this so I tried with the new motor before I installed it and it ran full speed.