Usually, the motor is connected to a rail or bracket that the window itself mounts to. On many cars when a power window stops working it can be:
1. Window motor goes out entirely - no noise/movement/etc.
2. A slider (often plastic) the window rides up and down on has broken (perhaps due to a lack of lubrication on a rail or just cheap plastic) - usually this manifests as a tilting window, etc.
3. Motor gear strips - this usually manifests as noise w/o movement or partial movement if just some of the teeth strip.
4. Some other part of the raising mechanism is messed up - depending the car it could be some combination of direct drive or cables, etc. The motor may run w/o movement.
Did you take the silver metal panel off once you got the door panel off in order to see inside the door cavity. Since the motor never touches the glass itself. It won't grind it, BUT with these frameless doors you could get into a situation where a window is fully up when you try to open it and it gets blocked by frame on body. The ugliest scenario occurs when a door window freaks out, is raised fully when OPEN and you shut the door slamming the glass into the body...oops.
