Garage Door Safety Sensors: Sun Glare, Humidity and Alignment
Garage door photo eye sensors send an infrared beam across the opening about six inches above the floor, and the door stops and reverses if the beam breaks while it is closing. They have been required on new openers since 1993. In Florida the two things that upset them most are low afternoon sun into a west facing garage and a film of humidity and dust on the lenses, and both can be fixed without replacing anything.
What they are
Two small units mounted on the track brackets near the floor, one on each side of the opening. One transmits an infrared beam, the other receives it.
While the door is closing, the opener watches that beam. Break it and the door stops and reverses at once.
They exist because garage doors have killed children. Federal rules made an entrapment protection system mandatory on residential openers manufactured after January 1993, and photo eyes are how essentially every manufacturer meets it. Our guide on garage door safety for children and pets covers the other two protections that sit alongside them.
Mounting height matters more than people think
Six inches above the floor, maximum.
The reason is specific. A child crawling under a closing door, or a dog asleep on the cool slab in the opening, is low. Sensors mounted at knee height look tidy and protect nothing at the height where the risk is.
If yours are higher, move them down. It takes minutes, and it is one of the first things we check on a tune-up.
Reading the indicator lights
Each sensor has a small light. Colors vary by brand, but the pattern is close to universal.
| What you see | What it means | What to do |
|---|---|---|
| Steady light on both | Aligned and working | Nothing |
| One steady, one flickering or dark | Out of alignment or the beam is blocked | Realign, clear the floor, wipe the lenses |
| Both dark | No power to the sensors | Check the wire and the terminals at the motor unit |
| Lights fine, door still will not close | Not a sensor problem | Force setting, travel limit or something binding |
If the opener light is also blinking, the count tells you which fault it has found. Our guide to opener blinking light codes lists the common ones.
How to align them
Loosen the wing nut on the bracket, move the sensor slowly until the light goes steady, and tighten it without letting it shift. If you cannot get a steady light, check for cobwebs on the lenses, something on the floor breaking the beam, or a bracket that has been kicked out of square.
Florida garages grow spider webs faster than most, and a web across a lens is enough. So is a leaf, a stray broom, or the corner of a storage bin.
Sun glare in west facing garages
This is the sensor call we get most in Florida, and it is almost never a broken part.
The receiving sensor is looking for a specific infrared signal. Late afternoon sun shining straight into its lens floods it with infrared and it can no longer tell whether the beam is there or not. The opener treats that as a blocked beam and refuses to close. The door works perfectly at 7 a.m. and again after dark, and refuses to close between about 5 and 7 p.m.
West facing garages get it worst, and the problem sharpens in the months when the sun sets lowest in the sky. Gulf coast neighborhoods with driveways facing the sunset see a lot of it.
Two fixes, both cheap:
- Swap the sensors. The sending unit does not care about sunlight. Move it to the sunny side and the receiver to the shaded side. Same brackets, same wires.
- Shade the receiver. A short length of pipe or a purpose made hood over the receiving lens blocks the sun without blocking the beam.
What we do not do is remove the sensors or tap them up out of the beam line. Households do this after weeks of frustration and then have a door with no protection at all.
Humidity, dust and salt on the lenses
The second Florida problem is a film. Humidity, fine dust, pollen in spring, lovebugs twice a year, and within a few miles of either coast a salt haze. Any of these can dim a lens enough that the beam reads as weak or broken, usually first thing in the morning when the air is thickest.
A dry microfiber cloth fixes it. Do not use anything abrasive, and do not spray cleaner into the housing.
Salt air also corrodes the small terminals where the wire meets the sensor and where it lands at the motor unit. A green or white crust on a terminal is a bad connection waiting to happen. Our guide on salt air and garage door corrosion covers what else it attacks.
The wire
It runs along the wall at floor level, which is exactly where it gets caught by bikes, stapled through during other work, and chewed by rodents. Look for damage before deciding the sensor is dead. A break in a low voltage wire costs almost nothing to fix and a new sensor pair will not cure it.
The reversal test
Sensors are not the only protection. The opener also monitors resistance, and it should reverse if the door meets an obstruction the beam did not see.
Test it: lay a piece of two by four flat on the floor in the opening and close the door onto it. The door should touch, stop and reverse.
If it does not, the down force is set too high. That setting exists to be adjusted, but adjusted properly, because an opener with the force turned up keeps pushing on whatever is under it. Run this test twice a year alongside the balance test.
When the sensors are fine and the door still misbehaves
A door that starts down and reverses halfway, with steady sensor lights, is usually a travel limit or a force setting, or a roller or hinge binding in the track. Our guides on a door that closes then reopens and a door that will not close separate the causes. All of it sits inside opener repair at $95 to $300.
If your opener has no sensors
It was made before 1993, which makes it over thirty years old. Parts are almost certainly no longer made for it, thirty Florida summers above 100°F have not been kind to its board, and it has no automatic way to stop for a child or a pet.
Replace it. A new opener is $275 to $600 installed through opener installation, and on a unit that age it is a safety decision rather than a repair decision. Our guide on how old is too old for an opener explains how to date yours.
Every price on this site is a starting price for a standard single door, listed on our price list, and you get a written estimate before any work begins. We cover the whole state, from Tampa Bay to Palm Beach and the Treasure Coast.
Related questions
How high should the sensors be mounted?
No more than six inches above the floor. Higher, and a small child or a pet lying under the door can be below the beam entirely, which defeats the purpose.
Why does my door only refuse to close in the late afternoon?
Direct sun into the receiving sensor. West facing garages get it worst, and the problem is sharpest in the months when the sun sets lowest. Swap the sending and receiving sensors so the receiver faces away from the sun, or fit a short shade tube over it. Both take ten minutes.
Can I bypass the sensors permanently?
Most openers let you close by holding the wall button continuously, which is meant for a one-off when a sensor has failed. Disabling them permanently removes the only automatic protection the door has for a child or an animal in the opening.
My sensors show steady lights but the door still reverses. Why?
Then it is the down force or the down travel limit. The opener is meeting resistance it reads as an obstruction, either because the limit sends the door too far into the floor or because something in the track is binding. That is a $95 to $300 opener repair, not a sensor problem.
How much does it cost to replace the sensors?
A new pair, installed and aligned, falls inside our opener repair price of $95 to $300. If the wire has been chewed or corroded along its length we replace that at the same visit.
