This is for a 89 Corvette, but same motors as our cars. The car has like 24,000 miles on it and the power window doesn't like to go up and down. If you bang on the door panel long enough in the right spot it works fine. I took off the door panel and cleaned the connections and it still does it!
Is it the motor that is having issues? Would a simple replacement motor do the trick?
Thanks!
Douglas

 

Apply +12V & ground directly to the two terminals on the motor. If the window still doesn't move, the motor or regulator has failed. If it moves properly, suspect something with the wiring or switches.