Garage Door Opener Motor Runs But the Door Won't Move?

The short answer

If your opener's motor runs but the door won't move, the mechanical connection between the motor and the door has broken somewhere.

The motor and its electronics are fine. Power gets in, the motor spins. Something between that spinning motor and the door itself gave out.

On chain and belt openers, the top suspect is a stripped nylon drive gear inside the motor head. Second is a trolley that popped off the emergency release. Third is a cracked carriage.

The fastest test costs nothing. Pull the red release cord, lift the door by hand, and see what happens.

What's actually going on inside

Let me walk you through what fails and why, in the order I'd check it in your garage.

The drive gear is the usual villain. It's a nylon gear that meshes with a metal worm gear on the motor shaft. Nylon is quieter than metal, but it wears, and after 10 to 15 years the teeth round off or strip clean. The motor spins, the worm gear spins, and the drive gear just sits there grinding.

You can confirm this in five minutes. Pop the light cover, remove the top housing, and look for white or gray plastic dust. That dust is your old gear teeth. It's the most common opener repair there is, and it's cheap.

Next is the emergency release. That red cord disconnects the door from the trolley so you can operate the door manually during a power outage. Pull it (or let a kid yank it) and the door and opener are no longer linked. The trolley slides, the door doesn't.

Then there's the carriage, the plastic piece that rides the rail and connects to the door arm. Cold weather and age crack these. When it breaks, the chain or belt moves fine, but there's nothing left to pull the door.

A snapped belt or a chain that jumped the sprocket does the same thing from the other direction: the loop won't move, so the trolley won't move.

And the one that trips people up: a broken torsion spring. When a spring breaks, the door suddenly weighs 150 to 250 pounds. The opener strains, hums, maybe reverses, and never lifts it. People blame the opener. The opener's innocent.

How to diagnose it, step by step

Work through this in order. Each step rules out a cause so you're not guessing.

Start with power off. Unplug the opener before you touch anything mechanical.

Now pull the red release cord and lift the door by hand. A balanced door in good shape lifts with about 10 pounds of effort and stays put halfway up. If it slams down or won't move, stop. You've got a spring problem, not an opener problem, and that's a pro call.

If the door lifts fine, re-engage the trolley (pull the cord back toward the motor, or run the opener until it clicks and locks). Test it. If it works now, someone just disconnected it. Done.

Still not moving? Plug in and watch the chain or belt while you cycle the opener. Moving loop with a still trolley means a broken carriage. A still loop with the motor running means a stripped gear, a jumped chain, or a snapped belt.

Unplug again, open the motor head, and inspect the drive gear. Shavings and worn teeth confirm the gear. Order the kit for your exact model number.

After any repair, reset the travel limits and force settings per your manual, then test the auto-reverse with a 2x4 laid flat under the door.

• Door lifts easily + trolley won't move: broken carriage
• Door lifts easily + loop won't move: stripped gear or slipped/broken chain or belt
• Door is heavy or stuck by hand: broken spring or seized track (not the opener)
• Plastic shavings in the head: stripped drive gear, confirmed

What it costs in 2026

Good news: this is one of the cheaper opener repairs, especially if you do it yourself.

A drive gear kit runs $15 to $40 for most common chain and belt openers. A replacement trolley or carriage is $25 to $70. A new belt or chain is $30 to $60. Basic hand tools are all you need.

So a DIY repair usually lands $20–$100 in parts, plus an hour or two of your time.

If you bring in a pro, expect $150–$500. That includes a service call fee of $75 to $150 just for the visit, plus parts and labor. A simple gear swap sits at the low end. Multiple failed parts or a hard-to-source unit pushes it up.

Compare that to a new opener: $200 to $500 installed for a solid belt-drive unit with modern safety sensors. If your opener is past 15 years and parts are getting scarce, replacement often wins on math and peace of mind.

DIY or call a pro?

This symptom is mostly DIY-friendly, with one hard line you shouldn't cross.

Re-engaging a trolley, swapping a drive gear, replacing a carriage, re-tensioning a chain: all reasonable for a handy homeowner with an hour and a socket set. The parts are cheap and the model-specific instructions are usually clear.

Where you stop is the springs. If the door is heavy or stuck by hand, a torsion spring has likely failed. Those springs are wound under enormous tension, and they injure people who guess. Call a licensed garage door tech for anything spring-related.

Also call a pro if the rail is bent, the sprocket bearing is shot, or you open the head and can't tell what you're looking at. There's no shame in a $150 service call to fix it right.

Can this wait?

Short answer: don't keep pressing the button. Once you know the door won't move, stop cycling the opener.

Every time you run the motor against a stuck door or a stripped gear, you heat up the motor windings. Keep at it and you'll cook the motor, turning a $30 gear job into a whole new opener.

If it's just a disengaged trolley, that's a two-minute fix and you're back in business today.

A stripped gear or broken carriage isn't an emergency, but plan to fix it within a week. In the meantime you can operate the door manually with the release cord pulled.

If a spring broke, treat it as urgent. A 200-pound door with no working spring is a hazard to anyone underneath it. Keep the door down and keep people clear until a pro handles it.

Why this tends to happen in winter

Cold makes plastic brittle. The nylon drive gear and the carriage both get stiffer and crack more easily below freezing.

A door that's a little sticky in the cold also makes the opener work harder, and that extra strain finishes off a gear that was already thin.

That's why we see a spike in these calls after the first hard freeze and again during peak summer use. If your opener is a decade old, expect the weak parts to give out when the weather's extreme.

Safety that actually matters here

Two hazards dominate this repair: electricity and stored spring energy.

Unplug the opener before you open the head or reach near the drive. It's easy to bump a control and start the motor with your hand inside.

Never touch torsion springs. They hold enough energy to break a wrist or worse. If the door won't lift by hand, that's a loaded-spring situation and a pro's job.

Don't stand under a partially raised door while testing anything. If a carriage or trolley lets go, the door drops.

After you finish the repair, test the auto-reverse. Lay a 2x4 flat on the floor under the door and run it down. It should hit the wood and reverse. If it doesn't, adjust the force setting and re-test before you trust it.

How we put this together

This guide reflects how a field tech actually diagnoses a running motor with a dead door: physical checks first, cheapest and most common causes ruled out early.

Cost ranges are 2026 US estimates for common residential chain and belt openers. Your parts and labor will vary by region and by how obscure your model is.

We deliberately draw a hard line at torsion springs because that's where DIY confidence gets people hurt. Everything on the opener side of the release cord is fair game for a careful homeowner. The door and its springs are not.