Garage door won't close and the opener blinks: what to check first

You press the button, the opener light blinks, and the door stays up or stops short of the floor. It is frustrating, and it is also the opener doing its job. Most openers sold in the U.S. today have a sensor that refuses to close the door when something might be in the way, so a blinking light usually points to that sensor, not to a dead motor.

This guide covers the checks a homeowner can do without a license: clear the beam, clean and realign the sensors, read the blink code in your manual, and run a reversal test. It also marks the point where the job belongs to a garage door pro. Anything involving the springs, cables, brackets or the balance of the door falls on the pro side of that line.

What's going on

Congress required entrapment protection on openers made for U.S. sale on or after January 1, 1991, and CPSC's later final rules required revised protection on residential openers made on or after January 1, 1993. One common form of that protection is an external device, such as an electric eye, that senses an obstruction without touching it. In practice that means a pair of small sensors near the floor on either side of the door, with an invisible beam between them.

If something breaks that beam, or the two sensors no longer point at each other, the opener will not close the door. Many openers show this by blinking a light. The exact meaning of a given blink pattern is set by the manufacturer, so your manual is the authority on it.

There is a reason for the strictness. CPSC had reports of 54 children aged two to 14 who died entrapped under doors with automatic openers since 1982, as of 1992. An industry coalition leader called a garage door the largest moving object in the home. A sensor that stops the door is a feature, so the goal here is to fix it and never to bypass it.

What you can safely check or fix

These steps need no tools beyond a cloth and, for the last one, a piece of wood. Keep the door area clear of children and pets while you work, and keep the remotes out of their reach.

1. Make sure nobody and nothing is under the door, then stand clear of its path.
2. Look along the floor line between the two sensors and move anything that could cross the beam, such as a bag, a bin, a tool or a hose.
3. Check that both sensors are still mounted firmly where they were installed and have not been knocked sideways.
4. Look at the small indicator light on each sensor. Your manual says what each light should show when the beam is healthy.
5. Wipe each sensor lens gently with a soft, dry cloth, following the cleaning advice in your manual, if dirt, a cobweb or sun glare could be in the way.
6. Point each sensor back at the other as the manual describes, then try the door again.
7. Read the blink code. Count the blinks or note the pattern, then match it to the table in your manual. If you no longer have the manual, CPSC says you can get a copy from the dealer or manufacturer.
8. Check how the opener is set up. Some openers have a constant-contact option, where you must hold the wall button for the door to close, and with that option the remote will not close the door.
9. Once the door closes normally, run the reversal test. Place a two-inch wooden block in the door's path and close the door. It should promptly reverse when it meets the block. If it does not, adjustments or repairs are needed, and you should follow the manual's adjustment steps or have a professional inspect it.

CPSC advises repeating the reversal test monthly, not only when something goes wrong.

Where to stop and call a pro

Sensors and blink codes are the opener's electronics. The door itself is a different matter. If the opener behaves but the door is the problem, or your sensor fixes do not help, the next steps are not a homeowner job.

Stop here: if the problem involves the springs, cables, brackets or the balance of the door, call a garage door pro. Do not loosen, adjust or remove any of these parts yourself.

These parts hold the weight of the door under tension, and mistakes with them can cause serious injury. That is why this guide gives no steps for them.

CPSC does describe one safe look at the door: disconnect the opener as the manual instructs, then manually open and close the door. A balanced door moves smoothly. If it feels very heavy, drops, binds or rides unevenly, leave it alone and call a pro. The cause is likely in the parts above.

Call a pro, or consider replacement, in these cases too:

• The door fails the reversal test after you have followed the manual's adjustment steps.
• The opener is old. CPSC says older reversing devices cannot be adjusted or repaired to match the safety of openers made in 1982 or later.
• The opener has no automatic reversal at all. A CPSC chairman said such openers should be replaced immediately.
• The opener opens and closes the door normally. CPSC warns that this alone does not prove it is safe, so a monthly reversal test still matters.

To find a licensed pro in your state, use the Find a Pro search on this site, which links each listing to the state's own license lookup.

What to tell the pro

A clear description saves time on the phone and on the visit. Have these ready:

• What the opener does when you press the button: blinks, stops short, or reverses.
• The blink pattern or count, and what your manual says it means.
• What you already tried: cleared the beam, cleaned and realigned the sensors, and the result.
• How the reversal test went, including whether the door reversed promptly on a two-inch wooden block.
• What you felt if you disconnected the opener and moved the door by hand: smooth, heavy, uneven or stuck.
• The opener's make, model and label details, including the safety label, which CPSC says lets consumers tell complying units from non-complying ones.

Keep the manual or a copy of it nearby. If a pro suggests replacing the opener, ask which entrapment protection the new unit has, such as an optional floor-level electric eye that reverses a closing door when an object crosses its path, which CPSC recommends.

Keep it safe at home

Between repairs, a few habits from CPSC help. Teach children about garage door safety, keep transmitters and remotes out of their reach, and keep remotes locked in the car away from children. CPSC also advises moving the wall switch high above the floor. Test the reversal feature monthly, and treat a blinking opener as a reason to look, not to work around the sensor.

Quick answers

Why does my garage door opener blink and not close?

Often a safety sensor is blocked or misaligned, since an electric eye senses an obstruction without touching it. Check the beam, then match the blink pattern to your manual.

How do I test that my garage door reverses?

Place a two-inch wooden block in the door's path and close the door. It should promptly reverse, and CPSC advises testing monthly.

When should I call a garage door pro?

Call one for springs, cables, brackets or door balance, or if the door fails the reversal test after you follow the manual's adjustments.