The Garage Door Opener Hums but Doesn’t Operate

Humming may be a good sign – you know it has power. The unit may simply be bound up. Check the moving parts to ensure the rails aren’t blocked and the armature is connected to the garage door. Ensure the unit is engaged, not in manual mode. Another possibility is, again, the force adjustment. Old, weak springs may shift much of the burden for lifting and lowering the door to the opener motor and drive system. While the unit may be able to handle the weight, then again, it may not. The result will be a straining motor that fails to open or close the door. Tweak the force adjustment to solve this problem.
A handy way to determine if the fault lies in the opener or the door is to eliminate the opener. Pull the emergency release handle hanging from the overhead unit to disengage it and allow the door to open and close manually. Lift and lower the door, testing the spring and rail systems. Your door should stay at any point of travel, when released, on its own. If it doesn’t and previous steps fail to fix the problem, the springs are too worn and need replacement.
If, however, the door stays where it’s left and moves up and down smoothly, the problem is likely an internal component in the garage door opener unit itself. Keep the setting on manual, so you can continue to use your garage, and consult a qualified professional.

The Garage Door Motor Fails to Stop Running

It probably comes as no surprise: If the door opens or closes but the motor continues to run, the limit switch is probably to blame. Adjust the switch, either on the rear of the opener unit or on the track, and try the opener again to confirm the solution.

The Garage Door Reverses Before or After Closing

If the garage door hits the floor and reverses to open again, check the close limit switch and adjust accordingly. When it reverses before even hitting the floor, a possible cause is another adjustment feature on the opener unit called the “close force adjustment.”
As your garage door gets older, the springs wear out. The result is irregular opening and closing. The solution is to increase the force setting on your opener.
Climb a stepladder to reach the garage door opener and look for the knobs on the rear of the unit. Turn the desired control clockwise slightly to adjust and retest the door. Continue turning, one at a time and in small increments, until the door opens and closes properly and stays in position.

The Garage Door Fails to Completely Open or Close

When the door refuses to lift or lower completely, the culprit might again be the safety sensors. If the sensors are operating properly – looking again to see if the lights shine red and green and are facing each other and aligned – a likely cause is one of the limit switches.
The exact placement and appearance of the limit switch depends on the specific garage door opener. Typically, you can find limit switches on the back of the garage door opener unit, the box attached to the door track overhead. Use a stepladder to reach the switches, small plastic screws marked up and down, and turn to adjust. On some brands, the switches are instead mounted on the rail extending between the door and opener unit. Loosen the switch and move either closer to or farther from the unit, then tighten with a screwdriver. Test the garage door opener after adjustment of either to see if this solves the problem.