A door that won't close — or starts down and then reverses back up — is usually the safety system doing its job, not a broken door. The good news: the most common cause is something you can often fix yourself in a couple of minutes.
Check the safety sensors first
Every modern garage door has two small photo-eye sensors near the floor on each side, connected by an invisible beam. If anything breaks that beam — a leaf, a trash can, a cobweb, or a bracket that got bumped out of alignment — the door refuses to close and reverses as a safety measure. Look for a blinking light on one of the sensors; that's the tell.
Clear anything in the path, wipe the lenses, and gently nudge the sensors so they point straight at each other (a steady, non-blinking light on both usually means they're aligned). This fixes a large share of "won't close" calls.
If it's not the sensors
- Close-limit setting — the opener thinks the floor is farther down than it is and reverses; this is an adjustment on the opener.
- Track obstruction or a bent track section stopping the door partway.
- Worn rollers or a cable issue making the door bind near the bottom.
- A door out of balance from a spring problem.
If clearing and realigning the sensors doesn't do it, the limit and track adjustments are quick for a pro. Describe what you see — does it reverse immediately, stop partway, is a sensor light blinking — and a technician can pinpoint it fast.
Describe the problem — Roger matches you to one vetted local pro and books it. $0 to you.
Common questions
- Why does my garage door start to close then go back up?
- That's almost always the safety sensors near the floor detecting a blocked or misaligned beam. Clear the path, clean the lenses, and align the two sensors so their lights stop blinking.
- Where are the garage door safety sensors?
- They're two small photo-eyes mounted a few inches off the floor on each side of the door opening, wired to the opener. A blinking light on one usually means they're out of alignment or blocked.
- Can I fix a garage door that won't close myself?
- Often yes — if it's the sensors, clearing and realigning them is a safe DIY. If it reverses with clear, aligned sensors, it's usually a limit or track adjustment better left to a pro.