Short answer: Most of the time a garage door that will not close (or reverses and the opener light blinks) is a safety sensor problem: the photo eyes near the floor are blocked, dirty or out of alignment. Clean the lenses, remove anything in the beam, and make sure both sensor lights are solid. If the sensors are fine, check the track, the remote and the close-limit setting. Broken springs or cables are a job for a pro.
Quick diagnosis
| What you notice | Most likely cause | What to check | Call a pro? |
|---|---|---|---|
| Door goes down a bit, then reverses; opener light blinks | Safety sensors blocked or misaligned | Clean lenses; check sensor lights | If they will not align |
| Closes with the wall button held, not the remote | Sensor or remote issue | Check sensors, then remote battery | Rarely |
| Door stops or reverses near the floor | Close-limit or force setting | See opener manual | If unsure |
| Door is crooked or jumps the track | Track or roller damage, or a broken cable | Do not operate it | Yes |
| Opener hums but door does not move | Broken spring or disconnected trolley | Do not lift it | Yes |
Check the safety sensors first
- Look at the two small sensors near the bottom of the tracks. Each has a light.
- Remove anything in the beam, including cobwebs, leaves or items stored nearby.
- Wipe the lenses with a soft cloth.
- If a light is off or flickering, gently adjust that sensor until it is solid. Make sure wires are connected.
Why the sensors matter
Federal rules require automatic reversing on residential openers, and CPSC warns that openers that do not reverse can trap and injure people, especially children. Never tape over or bypass sensors.
Other causes
- Weak remote battery (try the wall button).
- Close-limit setting that thinks the floor is higher than it is.
- Bent track or worn rollers.
- A disengaged trolley after someone pulled the emergency release.
When to call a professional
- A spring is broken, or a cable is loose or frayed. These are under high tension and dangerous.
- The door is off the track or crooked.
- The opener does not respond after the sensors and remote are checked.
What it usually costs
HomeGuide (2026) lists garage door repair at about $125 to $290 on average, sensor repair about $85 to $100, spring replacement $120 to $350, and opener repair $75 to $300.
Frequently asked questions
Why does my garage door close only when I hold the button?
Holding the wall button overrides the sensors on many openers. It usually means the safety sensors are blocked or misaligned.
Can I fix a broken garage door spring myself?
It is not recommended. Springs store enormous tension and can cause serious injury. Call a trained technician.
Related problems
Sources
- Angi: Why is my garage door sensor not working?
- U.S. CPSC: Non-reversing automatic garage door openers are a hazard (PDF)
- LiftMaster: UL 325 safety standards
- HomeGuide: Garage door repair cost (2026)
This guide is general information, not a substitute for an inspection by a licensed professional. See our disclaimer.