Garage Door Sensors Not Working: Why the Door Reverses

A door that starts closing, changes its mind and goes straight back up is the most common call we get that the owner could often have solved in five minutes. Here is how to tell which one you have.

What the sensors are

Since the early nineties every residential opener in North America has two small photo eye sensors, one either side of the opening, about six inches off the floor. One sends an infrared beam, the other receives it. Break that beam and the door will not close. It is the safety feature that stops a closing door on a child or a pet.

When a door reverses for no visible reason, the opener almost always believes that beam is broken.

The five minute checks

• Look at the small lights on both sensors. Typically one is steady and the other indicates alignment. If either is off or flickering, that is your answer.

• Clear the path. A bin, a bike wheel, a coiled hose or a snow shovel leaning in the beam is the single most common cause.

• Wipe both lenses. Cobwebs, road salt film and dust all scatter the beam, and a dry cloth is enough.

• Check alignment. Sensors get knocked by cars, bins and kids, and both must point straight at each other. A few degrees is enough to break the link.

• Look for low winter sun shining directly into the receiving lens. It is uncommon, but it happens, and it comes and goes at the same time each day.

Do those five and a good share of reversing doors start behaving again.

When it is not the sensors

If the sensor lights are healthy and the path is clear, the opener may be reversing on force feedback instead. It senses resistance and assumes it has hit something, and that resistance is usually real: binding rollers, track out of alignment, or springs that have lost tension so the door is heavier than the opener expects.

A quick way to tell them apart. Disconnect the opener with the manual release and lift the door by hand. A balanced door moves smoothly and stays put around waist height. If it is heavy, drags, or slams down, the problem is the door rather than the electronics.

What not to do

Do not disable or bypass the sensors, and do not tape them facing each other on the same side of the opening. It works, which is exactly the problem, because it removes the only thing preventing the door closing on someone. It is also against code.

Still reversing?

If the lights are fine, the path is clear and the door is heavy by hand, it is a spring or track problem and it needs someone with the right tools. Springs are the one part of a garage door that genuinely injures people.

Get a real answer on your door

Modern Empire Doors has served the GTA since 2018 from 138 Yorkland St, Richmond Hill. Text a photo of the door from outside and one from inside the garage to 647-323-1826 and we will tell you what you are actually dealing with.

• Call or text: 647-323-1826

• Open 24/7, including weekends

• Richmond Hill, Vaughan, Markham, Toronto, Aurora, Newmarket, York Region and Durham Region