A door that stops partway or reverses right before closing is almost always a sensor or track issue, not a motor problem.
Blocked or dirty safety sensors
This is the number one cause. The two sensors near the bottom of the tracks need a clear line of sight to each other. Dust, spider webs, or even direct sunlight hitting one of them can cause a false reading and stop the door.
Wipe the sensor lenses with a soft cloth and clear anything nearby that might block the beam. This fixes it more often than people expect.
Misaligned sensors
If the sensors got bumped (a bike, a ladder, a kid’s toy), they might not be pointing at each other anymore. Both should have a solid, steady light. A blinking light usually means misalignment.
Close-limit setting is off
Openers have a limit switch that tells the motor how far to travel before stopping. If this is set wrong, the door might stop short every time, even with nothing blocking it.
Obstruction in the track
Check the tracks for debris, a bent section, or anything physically stopping the rollers.
Worn rollers or hinges
Old, dry, or damaged rollers can create enough resistance that the door struggles near the bottom of its travel.
When to call someone
If cleaning the sensors and checking for obstructions doesn’t fix it, the limit settings or the track itself likely need a professional look. This isn’t usually an expensive fix. Track and sensor issues are typically the least costly garage door repairs.