The timing is too low or it has the wrong spark plugs in it.
You gotta start by figuring out what's wrong with it. You need to determine if it's the blower motor itself, or the power supply, then troubleshoot to determine the exact cause.
You probably missed the contact on the switch in the door panel. Check it out by using a 12 V power cable to turn the motor both directions. If that doesn't work you probably need a new motor for that window.
wiper motor or the bolts holding it tight.
something wrong with something in your power steering more than likely, get it checked out.
There is no power go to the motor. Test the wires to see if there is power to it.
the power leads were wired wrong
blower resistor is bad
I would suspect an intermittent short in the wiring to the power window motor in the section between the door and the door jam.
check all the fuses some times they are labled wrong
I have a 2003 astro with the same problem, it was the blower motor
you probably have one of a couple things wrong, bad ground,bad motor,or switch. try cleaning the ground and conectors,or feal the motor to see if its hot, or check to see if you have power at the motor and follow it on up if it doesnt till you find the power loss
You may or you may not. It all depends on the task you are using the motor. If speed is not a concern for you then you may, but for sensitive systems where changes in motor speed affects the system then you may not. The reason is that the frequency of the power supply affects the motor speed. Frequency is directly proportional to speed.