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Garage door won't close? A safety-first troubleshooting FAQ

A door that stops, reverses, or refuses to close is one of the most common garage door calls in Coral Springs, Parkland, Coconut Creek, and Margate. Many causes are simple and safe to check yourself. A few involve parts under heavy tension that only a trained technician should touch. This FAQ walks through both.

Why does my door go down, then reverse back up?

That's usually the opener's safety system doing its job. Under the federal safety standard for residential garage door openers (16 CFR Part 1211, based on UL 325), openers must reverse a closing door within two seconds after it hits a 2-inch-high object on the floor, and must reopen the door if it hasn't fully closed within 30 seconds of starting down. Openers made on or after January 1, 1993 also need a second layer of protection, usually the "electric eye" photo sensors near the floor. So a reversing door is often reacting to something it thinks is in the way.

What should I check first?

• Anything in the door's path. Bins, bikes, a hose, or a lip of debris on the floor can trigger a reversal.
• The trolley and rail. Chamberlain's support guide says to check the opener's trolley and rail for anything stuck that could stop movement.
• The opener lights. On many Chamberlain and LiftMaster openers, lights flashing 10 times when you try to close point to the safety sensors, while newer Security+ 2.0 models may beep and flash 5 times for an obstruction. Other brands use different codes, so check your manual.

How do I check the safety sensors?

• Find the two small sensors at the bottom of each side of the door opening.
• Gently clean the lenses with a soft cloth and clear anything blocking the beam, including cobwebs and leaves.
• Look at the sensor LEDs. On current Chamberlain Group sensors, the sending sensor shows a steady amber light and the receiving sensor a steady green light when aligned. An off or blinking receiver light usually means misalignment, an obstruction, or a wiring problem.
• To realign, loosen the bracket's wing nut slightly, aim the sensors straight at each other until the receiver's light is steady, then tighten it again.

The sensor lights look fine, but it still won't close. Now what?

Look for the door binding in its tracks, a locked manual latch, or a door that suddenly feels much heavier than usual. Opener force and travel limits can also be out of adjustment, but Chamberlain warns that setting too much force interferes with the safety reversal system. If adjustment is needed, follow your opener's manual exactly or have a technician do it.

When should I stop and call a professional?

• You hear a loud bang and the door won't lift, or you see a gap in a torsion spring above the door. That's usually a broken spring.
• A cable is frayed, loose, or off its drum.
• The door is crooked or has come off its track.
• The sensor wire is damaged. Chamberlain's diagnostic charts point to shorted or reversed sensor wires as a cause of some error codes.

Springs and cables hold enough tension to cause serious injury, so don't loosen, unbolt, or adjust them yourself. For typical prices, see our North Broward garage door repair cost guide.

Can I close the door by hand?

Openers are required to have a manual release, usually a red cord hanging from the trolley. Pulling it disconnects the door from the opener so you can move the door by hand, which helps during a power outage or storm. Only do this with the door fully closed if you can, because a door with a broken spring can drop fast once released. Hurricane-rated doors in Broward's High-Velocity Hurricane Zone are often heavier and reinforced, so take extra care.

How often should I test the safety reverse?

The U.S. Consumer Product Safety Commission recommends testing the reversing feature monthly. Follow your opener's manual. A common check is placing a 2-inch object, like a flat piece of wood, on the floor under the door and closing it. The door should reverse when it touches the object. Also wave something through the sensor beam while the door is closing; it should stop and reverse. If either test fails, stop using the opener's automatic close and get it inspected.

Sources

• eCFR: 16 CFR Part 1211, Safety Standard for Automatic Residential Garage Door Operators
• CPSC: safety standard for garage door openers (2-second reverse, 30-second reopen, manual release)
• CPSC: final rules for openers made on or after January 1, 1993, and monthly testing advice
• Chamberlain Group: resolving a close error (obstructions, sensor flash codes)
• Chamberlain Group: why won't my garage door fully close

Published 2026-10-20. This is general information, not legal or engineering advice; confirm current requirements with your city's building department.