Garage door reverses or will not close: check the path, then the sensors

What the door is telling you

An opener that reverses or will not close is working as designed when it senses something in the way. It senses in two separate ways. The photo eyes, one on each side of the opening near the floor, send a beam across the doorway, and a broken beam makes the door stop and go back up. Separately, the opener watches how hard it is working, and a door that meets resistance on the way down reverses. A door that reverses with nothing in the way points to one of those two systems, or to the door itself.

We have no figure on which cause is most common, so we name none.

Start with what is in the way

Clear the opening. A bag, a bike wheel, a hose, snow or ice at the bottom of the door, a dangling bit of weather seal, or a toy can all do it. Look along the floor under the door for anything that sits in the path of the beam or of the door’s bottom edge. Close the door again with the wall button and see whether it behaves differently.

Then the eyes

Each eye has a small lens and may have an indicator light. Wipe both lenses with a soft cloth. The two eyes should face each other and aim straight across, not at the floor or the wall. A bumped bracket can tilt an eye. Follow the wire from each eye to the opener and check for staples or a nick in the insulation. The manufacturer’s manual will say what the light patterns mean; follow it rather than guessing.

DASMA says the photo eyes should be no higher than six inches above the floor. If yours sit higher, tell the company that services the door. Do not move them yourself to a position the manual does not show. The same DASMA guidance puts the wall button at least five feet above floors, landings, steps or adjacent walking surfaces, out of reach of children, so mention a low button to the company as well.

Verdict: safe to look at yourself, then call if it persists. The checks above involve no springs, cables or brackets. Stop there.

Never bypass the eyes

Under the federal rule, vertically moving openers must meet one of three requirements for secondary entrapment protection: a constant-pressure close control, a means of connecting an external protection device such as a photoelectric sensor or an edge sensor, or approved inherent secondary protection. The circuits have to meet UL 991 or the entrapment supplement to UL 325. DASMA adds that since 1993 openers must include a second safety reversing feature such as photoelectric eyes.

So the eyes are required equipment and not an accessory. Do not tape over them or unplug them. A recall shows why: in February 2023 the Chamberlain Group recalled about 96,400 LiftMaster myQ garage door control panels because secondary entrapment protection could fail and let the door close with an obstruction present. No injuries were reported in the United States. It shows the feature failing and says nothing about any brand you own.

When the door will not reverse at all

The reversal test is separate from the eyes. The owner instructions the federal rule requires say the door must reverse on contact with a 1 1/2 inch object or a 2 by 4 laid flat, and that you should test monthly. See the reversal test guide. DASMA says a door that does not reverse readily after touching an obstruction may have the sensitivity set wrongly, which is dangerous, and recommends that a trained door systems technician do the adjustment. Until that is done, stop using the opener’s close function.

Door problems that look like opener problems

A door that reverses or stalls may be out of balance, and that is not a sensor problem. DASMA says that if the door is heavy or needs two hands, it is probably out of balance, and “the answer is not a more powerful garage door opener.” A door that is off its track, hangs low on one side or scrapes will also stop. Those faults involve springs, cables and brackets, which DASMA calls dangerous and says only trained professionals should repair. Do not try to lift the door to test it. Read the bang and the broken spring if you heard a noise.

Power and wiring

If the opener shows no light at all, that points to power, not sensors. Check the plug and the breaker. If there is no suitable outlet, the federal instructions for openers not equipped for permanent wiring say to contact a licensed electrician to install a suitable receptacle. See opener repair for the visit.

Write down what you saw

Before you phone, note where the door reverses (at the bottom or partway down), whether the opener lights flash, what the eyes show (a steady light or none) and how often it happens (every cycle or only some). Photograph the eyes from where you stand, and the label on the opener showing its model and date. The description also helps you notice if a quote does not match the symptom. If you have recently had work done on the door, mention that too.

When to call

Call if the door still reverses with a clear path and clean, aligned eyes, if an eye’s light stays off or blinks after cleaning, if the wire is damaged, if the door fails the board test, or if anything about the door’s balance seems wrong. On the call, say what you did, what the lights do, when it started, and how the door did on the monthly reversal test the last time you ran it. Ask what the call-out fee covers and for the price in writing before the work starts. Our estimate for a sensor visit is $130 to $260 per job, a model and not a quote; the safety sensors page shows how it is built.

If the door is stuck open with a car or person under it, or you are worried about security overnight, see the emergency page instead.