[SoCal LS-L]

EZ test:

Pull the release so the door goes up and down manually. Observe smoothness of glide during up and down motion, and relative weight of door. If its ok, then discount any problem with spring or rollers.

Then operate motor while door is still disconnected, if it still does not move in reverse, motor is kaput. If it does go in reverse, allow it to go through up and down motions a few times, then reconnect door and try operation with load of door on motor. If it still does not reverse under load, motor is kaput.