Garage Door Opener Hums but the Door Won't Move? What the Sound Tells You

You press the button, the opener makes a noise, and the door doesn't budge. That noise is useful. What you hear, and what moves or doesn't move, narrows the cause down to a handful of parts. Here is how to read it, which fixes take a minute, and which ones need a technician.

Start Here: What Do You Hear, and What Moves?

1. The motor runs and the chain or belt moves, but the door stays put

The door is almost certainly disconnected from the opener. Someone pulled the red emergency release cord, maybe during a power outage or to open the door by hand, and the trolley that rides along the rail is no longer latched to the door. Watch the rail while the opener runs: if the part on the chain travels along and the arm attached to the door doesn't, that's the cause.

The fix: close the door fully, then reconnect it. On most openers you pull the release cord once more to set the latch and then run the opener; the trolley catches the door's carriage with a click as it passes. The exact direction of the pull differs between LiftMaster, Chamberlain, Genie and Craftsman models, so check the label on the cord or the manual. Our power outage guide walks through reconnecting step by step.

If the trolley is latched and the door still doesn't move, look at the arm between the trolley and the door. A bent arm or a sheared bolt at the bracket on the top of the door will do the same thing, and that needs a repair.

2. The motor runs, but the chain or belt doesn't move

You hear the motor spinning, sometimes with a grinding sound, but nothing on the rail moves. On chain- and belt-drive openers this usually means the drive gear has stripped. Many openers use a nylon gear inside the motor head, and over the years its teeth wear down. It happens sooner when the door is heavy or out of balance, because the opener has been doing the springs' job.

A stripped gear is a common, repairable fault. It's worth checking the door's balance at the same time: if the door is heavy, a new gear will wear out the same way.

3. A hum or buzz, with no movement at all

The opener has power but the motor isn't turning. The usual causes:

• A failed start capacitor. Openers with an AC motor need a capacitor to get the motor turning. When it weakens, often after a power surge or simply with age, the motor hums but won't start. Capacitors hold a charge even when unplugged, so this is a job for a technician.
• The door is locked. Many doors have a slide bolt on the inside or a T-handle lock on the outside. If one is engaged, the opener hums and strains against it, then stops or reverses. Check both sides of the door.
• The door is frozen to the ground. After rain or snow in January, the rubber bottom seal can freeze to the slab. Don't force it: free the seal with warm air or a de-icer, and keep the area in front of the door clear of water.
• Something is jammed in the track. A bent track, a broken roller or an object in the track can stop the door before it starts.

4. The door starts to move, then stops or reverses

The opener moves the door a few inches and gives up. This is the opener's force limit doing its job: it senses more resistance than it should and stops. The resistance usually comes from:

• A broken spring or cable. The door is suddenly far heavier than the opener is meant to lift.
• The tracks or rollers. A bent track, a dry or broken roller, or a door that has come off its track.
• The safety sensors, if it reverses only on the way down. See our guides to sensor problems and to a door that won't close.

Don't turn the force setting up to push through it. The force limit is a safety feature; raising it to overpower a heavy door hides the real problem and makes the auto-reverse less safe.

Two-Minute Checks You Can Do Safely

1. Look at the springs and cables with the door closed. A gap in a spring or a slack cable means stop and call.
2. Check the trolley on the rail. Is it latched to the door's carriage?
3. Check the locks on the inside and outside of the door.
4. Unplug the opener for a minute and plug it back in. After a power blip, this resets the logic board.
5. Test the door by hand, but only if it's closed and the springs and cables look intact. Pull the release cord and lift the door. A healthy door rises smoothly and stays put about halfway. If it does, the door is fine and the problem is in the opener. If the door is very heavy or drops when you let go, the problem is the door. Lower it gently and leave it closed.

And one thing not to do: don't keep pressing the button. An opener that's straining gets hot, and many have a thermal cut-out that shuts the motor down for a while. Repeated tries won't fix anything and can finish off a gear that was only worn.

Repair the Opener or Replace It?

A stripped gear or a failed capacitor on an opener that is otherwise in good shape is usually worth repairing. If the opener is old, several parts are failing at once, or you want features it doesn't have, such as a quieter belt drive, smart-phone control or battery backup, replacing it may make more sense. Our guide to repairing vs. replacing a garage door opener goes through the decision.

Help in Philadelphia and South Jersey

Call and describe what you hear (a hum, a grind or a click) and what the chain or belt does. That usually tells us which part to bring, so most opener repairs are finished in one visit. We service all major brands, including LiftMaster, Chamberlain, Genie and Craftsman. See our garage door opener repair service.

Frequently Asked Questions

Why does my garage door opener hum but not open?

A hum with no movement usually means the motor isn't turning: a failed start capacitor, a door that is locked or frozen to the ground, or something jammed in the track. If the motor runs but the chain doesn't move, the drive gear has likely stripped. If the chain moves but the door doesn't, the door has been disconnected with the red release cord.

How do I reconnect my garage door to the opener after pulling the red cord?

Close the door fully, pull the release cord once more to set the latch (the direction differs by model; check the label or manual), then run the opener. The trolley catches the door's carriage with a click as it passes.

Can I replace a stripped garage door opener gear myself?

Gear kits exist and some handy homeowners do it, but it means opening the motor head with the opener unplugged and resetting the travel limits afterwards. Check the door's balance first: a heavy, unbalanced door is the usual reason gears strip.

Is it bad to keep pressing the garage door button when it won't open?

Yes. A straining opener overheats, and if a spring is broken, each try puts more strain on the motor, gear and cables. If the door hasn't moved after two or three tries, stop and find the cause.