Near the bottom of each garage door track, about six inches off the floor, sits a small plastic sensor. Those two devices are your door's safety sensors, also called photo eyes, and they are required by law on every opener made since the early 1990s. When they act up, your door refuses to close, and understanding them makes the fix quick.
How the Photo Eyes Work
The two sensors face each other across the door opening. One sends an invisible infrared beam, the other receives it. As long as the beam is unbroken, the opener knows the path is clear and lets the door close. If anything crosses that beam, a person, a pet, a trash can, the opener stops and reverses the door so it never closes on something. It is a simple, important safety feature.
Why the Door Reverses or Will Not Close
When the beam is blocked or the sensors cannot see each other, the door will not close and the opener usually flashes its lights or a sensor light blinks. The common causes are easy to check:
- Something in the way: a stray rake, a leaf, even a spider web across a lens can break the beam.
- Misalignment: a bump from a car or bike can knock a sensor so the two no longer point at each other.
- Dirty lenses: dust, pollen, or grime on the lens weakens the beam. Atlanta pollen season is a frequent culprit.
- Sun glare: direct afternoon sun hitting a lens can wash out the beam temporarily.
How to Fix Them Yourself
Most sensor problems take two minutes. Clear anything blocking the opening, then gently wipe both lenses with a soft cloth. Check the small indicator lights: most sensors glow a steady light when aligned and blink or go dark when not. If one is blinking, loosen its wing nut, adjust it until both lights are solid, and retighten. That realignment fixes the majority of cases.
When It Is Not the Sensors
If the lenses are clean, the sensors are aligned with solid lights, and the door still will not close, the problem may be a damaged sensor, a cut or pinched wire, or the opener's logic board. A door that reverses partway down for no obvious reason can also be a travel or force setting on the opener, or a mechanical snag in the tracks. Those are worth having a technician check. Our team handles opener and sensor repair, and a quick garage door maintenance visit keeps the sensors and the rest of the system tuned.
Door stuck open and the sensors checking out fine? Do not leave it open overnight. Our team provides same-day garage door repair across metro Atlanta with a free on-site estimate.