Why Your Garage Door Won't Close: Misaligned Photo Eyes
You hit the button. The door starts down. Then it stops, jerks, and goes right back up like it changed its mind. You try again—same thing. Now you're late, the car's sitting in the driveway, and the garage is wide open.
We get this call a lot. And more often than you'd think, the fix takes about two minutes. The problem is usually two small boxes near the floor that aren't looking at each other anymore.
What photo eyes actually do
Look at the bottom of your garage door track, one on each side, a few inches off the floor. Those are your safety sensors. Most people call them photo eyes.
One side sends an invisible infrared beam across the opening. The other side catches it. As long as the beam gets through, your opener knows the path is clear, and the door can close. The second something breaks that beam, like a kid, a pet, or a bike someone left in the way, the opener stops and sends the door back up.
Every residential opener sold in the U.S. since the early '90s has to have them. A closing garage door is one of the heaviest moving things in your house, and those two little sensors are a big part of what keeps it from landing on someone.
Why a crooked sensor keeps your door open
Here's the catch. Your opener can't tell the difference between a child standing in the doorway and a sensor that got knocked an inch out of line. Either way, the beam doesn't reach the other side. So the opener plays it safe and refuses to close.
It doesn't take much. These sensors are mounted low, right where life happens:
The trash can gets dragged past and clips one
A bike, mower, or kid's scooter bumps the bracket
Years of the door running up and down shake the mounting screws loose
Dust, cobwebs, or a mud splash cover the lens
Low sun hits the receiving eye and drowns out the beam (this one shows up every fall around here, when the sun sits low in the morning and late afternoon)
How to tell it's the sensors:
The door goes down a foot or two, then reverses
The opener light blinks after it fails to close
The door closes fine if you hold the wall button down the whole way
One or both of the little lights on the sensors are off or flickering instead of steady
That last one is the giveaway. On most openers, both sensors have a small LED. When they're lined up, both lights stay solid. If one is blinking or dark, they've lost each other.
What you can check yourself
This is one of the few garage door problems we're happy to see homeowners handle on their own. No springs, no cables, nothing under tension. Here's what we'd do:
Clear the path. Make sure nothing is sitting in the doorway or leaning against either sensor.
Wipe the lenses. A soft, dry cloth is all you need. Dirt and webs block more than you'd expect.
Check the lights. Note which sensor is blinking or dark. That's usually the one that got bumped.
Line them back up. Loosen the wing nut or screw on the bracket and slowly tilt the sensor until its light goes solid. Then tighten it back down without moving it. Both sensors should point straight at each other at the same height.
Test it. Close the door, then wave a broom handle through the beam while it's coming down. It should reverse right away. If it does, you're good.
If the low sun is your issue, the door will usually behave again once the sun moves. A small sun shield or swapping which side the receiving eye sits on can fix it for good.
One thing never to do: don't tape the sensors together, mount them up high, or bypass them to get the door to close. We've seen it. It works right up until the day it really matters.
When it's time to call us
Sometimes it's not alignment. Give us a call if:
Neither sensor light comes on at all
The lights stay off even after you realign them
The wires are chewed, pinched, or pulled loose (mice love garage wiring)
A bracket is bent or cracked
The door is also noisy, slow, or uneven on the way down
Those point to wiring, a failing sensor, or something bigger with the opener. Our licensed techs carry replacement sensors in the van and can usually knock it out in one visit.
Want to stop thinking about this stuff altogether? Door+ members get regular safety checks, and photo eye alignment is part of every visit. We catch it before it catches you.
ROLL Garage Door Co. serves homeowners across Maryland and DC. Won't the door close? Let's Roll. Book a visit or call us, and we'll get you back in motion.
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