Troubleshoot

Garage Door Opener Runs But the Door Won't Move? Here's Why

Affordable Door Co · October 2026 · OKC Metro

If you press the button and the opener motor hums or runs — you can hear it working — but the door doesn't move, the problem is almost always in the connection between the motor and the door, not the door itself. The most common causes are a stripped drive gear inside the opener, a broken or slipped belt or chain, the emergency-release cord left disengaged, a failing motor capacitor, or a broken spring that leaves the door too heavy for the opener to lift. Each has a different tell, and only some are safe to touch yourself.

A motor that spins while the door sits still is one of the most common opener calls we get, and it's easy to mistake for a "dead" opener. The good news: the motor is often fine. The bad news: a couple of the causes — a broken spring especially — are dangerous to test the wrong way. Here's how to read the symptoms and know which fix is a quick reset and which needs a technician.

1. The Emergency Release Is Disengaged

Start here, because it's the easiest and most common. Every opener has a red emergency-release cord hanging from the trolley — the piece that connects the door to the drive rail. Pull it, and the door disconnects from the opener so you can lift it by hand during a power outage. If someone pulled that cord and never re-engaged it, the motor and trolley will run the full length of the rail while the door stays put, disconnected. It sounds exactly like a serious failure but is a two-second fix.

To re-engage most openers, pull the release cord toward the door (or push the lever back) and then run the opener once — the trolley slides back until it clicks into the carriage and reconnects. If the door then works normally, that was it. If the trolley won't catch, move on to the next cause.

2. A Stripped Drive Gear (Chain- and Screw-Drive Openers)

Inside many openers is a small plastic drive gear that turns the sprocket the chain or screw rides on. It's designed to wear out before the motor does, so it's a common failure point — especially on older units and after years of Oklahoma summer heat, which softens the nylon and speeds up wear. When it strips, the motor spins freely and you'll often hear a distinct grinding or whirring while the chain or door doesn't move. Sometimes you'll see fine plastic shavings on the floor beneath the opener.

A stripped gear isn't a reason to replace the whole opener. On many models the gear-and-sprocket assembly can be rebuilt, which is far less than a new unit. Whether that's worth it depends on the opener's age and condition — a very old motor nearing the end of its life may be better replaced than rebuilt. A technician can open it up, confirm the stripped gear, and tell you honestly which way makes sense.

3. A Broken or Slipped Belt or Chain

Belt-drive and chain-drive openers move the trolley along the rail with — no surprise — a belt or a chain. If that belt snaps or the chain breaks or jumps off its sprocket, the motor and sprocket keep turning but nothing pulls the trolley, so the door stays still. Look up at the rail: a chain lying slack or pooled on the floor, or a belt hanging loose, is an obvious sign. A chain that's simply loose (not broken) can also skip under load and make a clatter without moving the door properly.

A broken belt or chain needs replacement, and a loose one needs proper re-tensioning — both are straightforward for a technician but fiddly to get right by hand, since over-tightening a chain wears the sprocket and puts strain back on that drive gear.

4. A Failing Motor Capacitor

Here the tell is different: instead of running freely, the motor hums or buzzes but doesn't actually turn, and it may trip nothing at all or feel like it's "trying." The capacitor is the component that gives the motor the jolt it needs to start spinning. When it weakens or fails, the motor gets power but can't get moving — so it sits there humming. Heat is again a factor; capacitors degrade faster in a hot garage, which is why these failures cluster in late summer here.

A capacitor sits in the opener's power circuit and can hold a charge even when unplugged, so this is not a DIY part to poke at. If the motor hums without turning, unplug the opener and have it diagnosed — a capacitor is an inexpensive part, but it needs to be discharged and replaced safely.

5. A Broken Spring (The Dangerous One)

Your garage door's springs — torsion springs above the door or extension springs along the tracks — do the real lifting. The opener only guides a door the springs have already balanced. When a spring breaks, the door effectively weighs well over a hundred pounds, and the opener simply can't lift it. Depending on the model, the motor may strain and stop, hum, run and reverse, or run a short distance and quit. People often blame the opener when the real failure is a snapped spring.

This is the one cause where continuing to hit the button does harm — you can burn out the very opener that's actually fine, and a door held up only by the opener can drop. If you pulled the release and the door was heavy or wouldn't stay up, or you see a visible gap in the torsion spring above the door, stop. Torsion springs are under extreme tension and are not a DIY repair; this needs a professional.

Oklahoma Heat Makes These Failures Cluster

There's a reason "opener runs but the door won't move" calls spike in an Oklahoma summer and into early fall. An uninsulated garage ceiling can sit above 100°F for weeks, and that sustained heat is hard on the two parts most likely to cause this: the nylon drive gear, which softens and strips faster, and the motor capacitor, which degrades quicker when it runs hot. A door that's been slowing down or straining all summer often gives out as the season turns. A little seasonal maintenance — checking chain tension, lubricating the rail, and having a worn opener looked at before it fails — heads off a lot of these.

When to Call a Professional

Re-engaging the emergency release is a safe DIY fix. Almost everything else here — a stripped gear, a broken belt or chain, a bad capacitor, and especially a broken spring — is work for a trained technician, both because getting it right takes the right parts and because springs and capacitors can injure you. If re-engaging the trolley didn't solve it, the fastest path is a diagnosis: a good tech can tell within minutes whether you're looking at a simple gear rebuild or a spring replacement. Our team handles garage door opener repair across the OKC metro and will tell you straight whether the opener is worth rebuilding or it's time for a new one.

The Quick Diagnosis Checklist

• ›Release cord: if the trolley runs the rail but the door stays put, the emergency release is disengaged — re-engage it first
• ›Grinding + plastic shavings: stripped drive gear — often rebuildable, not a full replacement
• ›Slack or broken chain/belt on the rail: needs replacement or proper re-tensioning
• ›Motor hums but won't turn: likely a failing capacitor — unplug it and have it checked
• ›Door heavy by hand or visible spring gap: broken spring — stop, don't force the opener, call a pro

Work through these in order and you'll usually know within a few minutes whether it's a quick reset or a repair. If it's not the release cord — or you'd rather not guess with springs and electrical parts — Affordable Door Co has kept OKC-metro doors and openers running since 1994, 24/7, with no after-hours surcharge and no trip fees across our service cities.

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