My Door Won't Close All The Way — What's Wrong?

You hit the button, the door starts to close, then about a foot from the ground it stops, reverses, and goes right back up. The opener light might flash 10 times. Sound familiar?

Nine times out of ten, this is the safety sensors — the two little eye-shaped boxes mounted near the floor on either side of the door. They’ve been required by federal law on every garage door opener since 1993, and they save lives. They also cause more service calls than any other single thing.

How to check the sensors yourself

Before you call me, try this — it takes 60 seconds and you might fix it for free.

1. Look at the LEDs. Each sensor has a small light. One should be solid green (the sender), the other solid red or amber (the receiver). If the receiver is flashing or off, the beam is broken.
2. Check for obstructions. A leaf, a spider web, a rake leaning against the track. Clear anything between the two eyes.
3. Wipe the lenses. Dust and condensation are the #1 culprits. Use a soft cloth — don’t soak it.
4. Check alignment. The sensors are on adjustable brackets. If one got bumped (kids’ bikes, lawnmower, etc.) it’s probably tilted. Loosen the wing nut, eyeball them at each other, retighten when both LEDs go solid.

If the LEDs go solid after that, you’re done. Try the door.

When it’s not the sensors

If the sensors check out but the door still bounces, a few other things to look at:

• Travel limits set wrong. The opener thinks the floor is higher than it actually is. Adjustable on most openers via a small dial or two buttons on the side.
• Worn or stretched cables. If the cables have play, the door won’t sit flat and the opener will reverse out of confusion.
• Spring tension off. A stretched-out torsion spring can make the door feel heavy at the bottom and trigger the auto-reverse.

When to call

If you’ve cleaned the sensors, checked alignment, and the LEDs are still wonky, the wires might be damaged or the sensor itself is shot. New sensors run about $35 in parts and 20 minutes of work to install and align. Most calls I take for this are in and out the same day.

Heads up: California now requires a battery backup on every new opener. If yours is older than 2019, ask me about it next time I’m out.

Sensors are simple but unforgiving. They’re trying to save you from closing a door on a kid or a pet — when in doubt, replace them. Don’t disable them.