The garage door reversing-on-close issue is one of the most common calls we get from late October through February. It feels personal — like the door has decided it doesn't trust you anymore — but it's almost never the door. It's the photo-eye sensors. And it's a thirty-second fix you can do yourself before you call anyone.

Save the service-call money for something better. Like halibut and chips at Pajo's on the Steveston wharf.

What the photo-eyes do

Down by the floor at each side of the door opening, about 15 cm (six inches) up, you'll see two small plastic eyes pointed at each other across the doorway. They're the safety beam. Openers have been built with them as standard since the early 1990s, when US safety rules made them effectively mandatory — they're what stops the door from closing on a kid, a cat, a hockey bag, or the recycling bin you left sticking out two inches too far.

The way they work is simple. One eye sends an infrared beam. The other eye receives it. If the beam is interrupted, the opener won't let the door close, and if the door is already closing and the beam breaks, the door reverses — that's the auto-reverse safety.

What goes wrong in November

Two things. Both involve water.

1. The lens gets foggy.

Fall fog on the Lower Mainland isn't just the fog you can see — it's airborne moisture that condenses on every cold surface for hours after the visible fog burns off. Your photo-eye lens is a cold plastic disc roughly the size of a dime, six inches off a cold concrete slab, facing into an unheated garage. Moisture loves it. By 7 a.m. the lens has a film of micro-condensation that scatters the infrared beam. The door reads it as obstruction. Door reverses.

2. The lens gets dusty, and the dust gets damp.

Garage floors are dirty. Cars track in road grit, leaves blow in, you sweep a few times a year and the rest of it just kind of accumulates. In summer the dust is dry and the beam punches through it. In fall, the dust gets damp from condensation, and damp dust on a lens is close to opaque. Beam can't get across. Door reverses.

Diagram of a garage door photo-eye sensor near the floor, with condensation forming on the lens and a damp paper towel wiping it clean.
The photo-eye is a dime-sized lens six inches off a cold slab on a foggy morning — of course it condenses. Damp paper towel, no chemicals.

The 30-second fix

Get a damp paper towel. Not wet — damp. Wring it out.

  1. Wipe the lens on the sender eye. One side has an indicator light that's on solid. That's the sender. Wipe it gently in a small circle. Don't push hard — the eye is on a swivel bracket and it'll knock out of alignment.
  2. Wipe the lens on the receiver eye. The other side. Indicator light may be flashing or off — that's the symptom you're fixing. Wipe gently.
  3. Dry both with a dry paper towel. No streaks, no residue.
  4. Check alignment. Both indicator lights should now be solid. If one is flashing, the eyes are pointed slightly off each other. Gently nudge the bracket until the light goes solid. They want to look at each other directly.

Test the door. It should close normally now.

⚠ A note on chemicals — Use water only. No Windex, no rubbing alcohol, no lens cleaner, definitely no Goo Gone. The plastic on photo-eye lenses is soft and most solvents will haze it permanently. A clouded lens scatters the beam constantly, which means the door will keep reversing forever and you'll need new eyes. Water and a soft cloth. That's the whole protocol.

If the fix didn't fix it

Three possibilities.

Possibility A — Alignment is off.

If after cleaning, one indicator light is still flashing, the eyes are looking past each other. This happens when somebody bumps the bracket with a kayak, a Costco run, or a kid's scooter. Gently bend the bracket back until the receiver light is solid. If it won't hold, the bracket may be cracked — that's about a $40 part and a job for an opener tech. (Not us — we only do springs.)

Possibility B — Sun in the lens.

This one hits west-facing garages — Tsawwassen and White Rock get it a lot. Late afternoon, low fall sun shines straight into the garage and onto the receiver, and it washes out the infrared beam. The door won't close while the sun is on the lens. The fix is a sun shield (a small cardboard or metal hood, $0 if you make it from a yogurt lid), or wait twenty minutes for the sun to drop below the roofline.

Possibility C — Wire damage.

If the receiver light is completely off, no indicator at all, the low-voltage wire from opener to eye has been cut, pinched, or chewed. Mice in the rafters love photo-eye wires for some reason — I think it's the warmth from the LED. Wire repair is about twenty minutes and the parts are cheap — again, that's an opener tech's job, not ours.

What this is not

This is not a spring problem. This is not an opener problem. This is not the door rejecting you personally. This is a sensor that needs a wipe. A surprising share of the "opener not working" calls we get from November through February turn out to be photo-eye fog. If you save one call-out a year by knowing this, that's a halibut dinner. If you save three, that's a halibut dinner with chowder.

The honest bit

The reason we tell you this — instead of, you know, charging you to come do it — is because that's how I was raised. My grandfather wouldn't have charged you for showing you how to tie a knot. My dad wouldn't have charged you for showing you where the roof was leaking. I'm not going to charge you to wipe a lens. Save the call for something that actually needs a wrench.

And when something does — a spring, a cable — call us. Same crew, same number, and the closest tech is usually 12 to 18 minutes away.