Driver Window Dont Roll All The Way Down on 1999 GMC Jimmy

How do i test a window motor without buying a new one first. The window sticks halfway dow then the motor spend like gears r missing but there r none missing and there is not any obstruction.

Asked by for the 1999 GMC Jimmy
Sounds like the window regulator is bad, Either way you'll need to pull the door panel to get to them, You can check repair prices here or locate a shop here