Why doesn't my garage door reverse when it hits something?

The door came down on a trash can, a bike, or a box and kept pushing instead of going back up. Or it stopped and sat there, pressing down. Either way, the opener's reversing system did not do its job.

Most garage door problems are an inconvenience. This one is a safety problem. A closing door is heavy, and the reverse is what keeps it from pinning a child, a pet, or a person. Stop using the opener until you know why it failed.

This guide covers home and business garage doors only.

Two systems are supposed to stop the door

A modern opener has two separate ways to protect whatever is under the door. They fail for different reasons, so it helps to know which one you are testing.

• The photo-eye sensors. The two small sensors near the floor on each side of the door send a beam across the opening. If something breaks the beam while the door is closing, the opener should stop and send the door back up before it ever touches anything.
• The contact reverse. If the door touches something solid on the way down, the opener feels the resistance and should reverse. This depends on the opener's force and travel limit settings, and on the door moving freely in the first place.

Test 1: the photo-eyes

• Open the door all the way and stand clear of it, inside the garage, with a clear view of the whole opening.
• Start the door closing with the wall button.
• While it is coming down, pass a broom handle or a cardboard box through the beam near the floor. Do not use your hand or foot.
• The door should stop and go back up. If it keeps closing, the sensors are not protecting the opening.

Test 2: the contact reverse

• Lay a piece of 2x4 lumber flat on the floor in the middle of the door's path, or use a roll of paper towels if you do not have a board.
• Close the door with the wall button and watch it.
• When the bottom of the door touches the board, it should reverse and go back up within a couple of seconds.
• If it stops on the board and stays there, or keeps pressing down, the contact reverse has failed. Open the door with the button and take the board out.
• Most opener manuals suggest running both tests about once a month, and after any repair, adjustment, or new opener.

What usually causes a failed test

• The sensors are mounted too high. They are meant to sit just above the floor. Sensors that were moved up out of the way, or mounted on the ceiling, cannot see a small child or a pet.
• The sensors were disconnected or tied together by someone before you. In older houses, a previous owner sometimes defeated the sensors to stop a door that kept reversing. That makes the door look fixed while removing the protection.
• The close force is set too high. Someone turned the force up to push a stiff or heavy door down, and now the opener keeps pushing against anything in its way.
• The close limit is set wrong. If the opener thinks the door reaches the floor sooner than it does, it can treat the board as the floor and stop instead of reversing.
• The door itself is the real problem. Worn rollers, a bent track, or weak springs make the door hard to move, and the opener's settings get pushed to compensate. The door needs to be fixed before the opener can be set correctly.
• The opener is very old. Openers built before the reversing rules came in may have no photo-eyes at all, or a reversing system that has worn out. On those, replacement is usually the answer, not a repair.

What you can safely check yourself

• Look at where the sensors are. They should face each other across the door opening, near the floor, on both sides. Note whether they are higher than that, mounted somewhere else, or missing.
• Look at the sensor lights. Steady lights on both usually mean they are lined up. A blinking or dark light means they are not seeing each other. Clean the lenses and line them up as the guide on a blinking sensor explains.
• Follow the thin sensor wires toward the opener as far as you can see them. Note any wires that look cut, twisted together, or connected straight to each other instead of running to both sensors.
• Find the model number on the opener's label and look up the manual. It shows where the sensors should be mounted and how the opener's settings work.

What not to do

• Do not turn the force setting up. A door that will not close is usually the safety system working. Turning the force up hides a door problem and makes the door more dangerous to anyone under it.
• Do not bypass, tie together, or move the sensors out of the way to make the door close. The sensors are the main thing keeping the door off a person.
• Do not test with your hand, your foot, or anyone's body. Use a board, a box, or a broom handle.
• Do not touch the springs, cables, or drums, even if you think the door is too heavy. That is pro-only work under high tension.
• Do not open the opener's motor housing. Anything inside it, and any wiring behind an electrical cover plate, is pro-only.

In the meantime

Until the door passes both tests, the safest choice is to leave it closed and unplug the opener. If you have to use it, run it only from the wall button, stand where you can see the whole opening, and do not walk away until the door is fully down. Keep the remotes away from children, and keep children, pets, and cars clear of the door while it moves.

Do not pull the red emergency release cord while the door is open. If a spring is weak or broken, the door can drop.

How it gets fixed, and what moves the price

A garage door technician starts with the door, not the opener. They check the balance, springs, cables, rollers, and tracks, because an opener can only be set correctly on a door that moves freely. Then they check the sensor mounting and wiring, set the force and travel limits to the manufacturer's settings, and run both tests in front of you.

Often the fix is re-mounting or replacing the sensors and resetting the opener. Sometimes the door needs work first, such as new rollers or spring service. On an old opener with no photo-eyes, or one that still fails after it has been set correctly, a new opener is usually the recommendation.

What moves the price is whether it is an adjustment or a part, whether the sensors or their wiring need replacing, whether the door needs spring, roller, or track work before the opener can be set, and whether the opener is old enough that parts are no longer made. An adjustment sits at the small end; door repairs or a new opener are more. The technician confirms the price in person after seeing the door.

Booking through Roger

Describe what happened: which test failed, whether the sensor lights are steady, blinking, or dark, where the sensors are mounted, roughly how old the opener is, and whether the door feels heavy or noisy. Roger books one vetted local garage door technician and confirms the appointment, so you know which company is coming. Home and business only.

You can describe the problem on rogerrepair.com and get one garage door pro booked.