Short answer
Garage door troubleshooting starts with the symptom. A door that will not close is usually a safety sensor issue. A loud bang and a heavy door point to a broken spring. A crooked, jammed door is likely off track. Homeowners can check sensors, batteries and power; springs, cables and tracks need a technician.
Key facts
- Chamberlain: when the opener light flashes and the door will not close, the safety reversing sensors or the LOCK button are the likely cause.[1]
- Chamberlain: a garage door that feels unusually heavy indicates a spring problem requiring professional service.[2]
- Clopay: if a garage door is off its tracks, stop operating it immediately and contact a trained technician.[3]
- HomeGuide (Jan 2026): most garage door repairs cost $150 to $350.[4]
Find your problem
| What you see or hear | Most likely cause | Guide |
|---|---|---|
| Door starts down, then reverses | Safety sensors blocked or misaligned[1] | Garage door won't open or close |
| Opener light flashes, door stays open | Sensors or the lock button[1] | Garage door won't open or close |
| Remote does nothing | Battery, lock mode or power | Garage door won't open or close |
| A loud bang, then the door is heavy or will not lift | Broken spring[3] | Broken garage door spring |
| Door hangs crooked, a cable is loose | Snapped cable or spring | Broken garage door spring |
| Door is jammed, rollers are out of the track | Off track[3] | Garage door off track |
| Noisy, jerky or slow | Wear, lubrication or hardware | Garage door maintenance |
What homeowners can safely check
Three checks are safe for most people:
- Safety sensors. Clear anything in the beam path, wipe the lenses and re-aim them until the lights are steady. Chamberlain says ten flashes of the opener light point to the sensors and two flashes mean the lock button is on[1].
- Remote and keypad. Replace the battery and make sure lock or vacation mode is off.
- Power. Test the outlet with a lamp and check the breaker.
The emergency release cord is a fourth check, with a strict rule. Chamberlain says to use it only when the door is fully closed, if possible, and never to pull it to raise or lower the door[2].
What to leave alone
Springs, cables, the bottom brackets and the tracks are tied to the door's counterbalance system. Springs are under high tension. Do not adjust, loosen or force any of them. Chamberlain says a door that feels unusually heavy points to a spring problem requiring professional service[2]. Clopay says to stop operating an off-track door immediately and call a trained technician[3].
Also leave the opener's force and limit settings to a technician unless your manual walks you through them. These settings work with the safety system. After any adjustment, the door must pass the reversal test: CPSC says a door that does not reverse on a 2x4 should be disengaged until it is adjusted, repaired or replaced[5].
What repairs cost
HomeGuide puts most garage door repairs at $150 to $350, with minimum service fees possible[4]. For prices by problem, see garage door repair cost. For springs specifically, see spring replacement cost.
Before the technician arrives
- Leave a broken or off-track door where it is, and keep people and cars clear.
- Note what happened: a bang, a car strike, a storm or a power outage.
- Take photos of the springs, cables and tracks from a safe distance.
- Ask for the service call fee and an itemized written quote before work starts.
When to call a pro
- A broken spring, a loose or snapped cable, or a door off its track.
- The door will not close after you clean and aim the sensors.
- The door fails the monthly auto-reverse test.
- The opener runs but the door does not move, and the release cord has not been pulled.
Sources
- Garage door opener light blinks but the door won't close, The Chamberlain Group (Chamberlain and LiftMaster support). Accessed 2026-10-15.
- How to manually open or close a garage door, The Chamberlain Group (Chamberlain and LiftMaster support). Accessed 2026-10-15.
- Why does my garage door get stuck?, Clopay. Accessed 2026-10-15.
- How much does garage door repair cost? (Jan 6, 2026), HomeGuide. Accessed 2026-10-15.
- Non-reversing automatic garage door openers are a hazard (Pub. 523), U.S. Consumer Product Safety Commission. Accessed 2026-10-15.
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