Match the Symptom
Door opens, then refuses to close and the opener light blinks
The sensors can't see each other
Door starts down, then goes back up
Something in the beam, or the door is binding
Door closes only if you hold the wall button down
Almost certainly the sensors
Door reverses right before it touches the floor
Travel limit set wrong or the door binds
Door closes, but the remote does nothing
A remote or lock button issue, not the sensors
What the Sensors Do
Every opener made in the last few decades has a pair of safety sensors, also called photo eyes, about six inches above the floor on each side of the door. One sends an invisible beam and the other receives it.
If anything breaks the beam while the door is closing, the opener stops and reverses. That's what keeps the door from coming down on a child, a pet or a car hood. It's a feature you want working.
Checks You Can Safely Do
- Clear the path. Move recycling bins, bikes, boxes and anything near the floor by the tracks.
- Clean the lenses. Wipe both with a soft cloth. In Durham, spring pollen and summer cobwebs are the usual culprits.
- Check the lights. Most sensors have a small light on each side. Both should glow steady. A dim or blinking light means they're out of line.
- Aim them. If a sensor got bumped, loosen its wing nut, point it at the other one until the light goes solid, and snug it back.
- Look at the wires. A wire chewed by a mouse or nicked by a weed trimmer near the floor will kill the signal.
- Try the wall button test. Hold the wall button down the whole way. If the door closes that way, the sensors are your problem.
Bright low sun shining straight into one sensor can also confuse it late in the day. Some homeowners solve that with a small shade over the receiving sensor.
When It Isn't the Sensors
If the sensors check out, the door may be binding as it comes down. A bent track, worn rollers or a tight spot makes the opener think it hit something, so it reverses.
The wrong fix is turning the opener's force way up.
That hides the real problem and can stop the door from reversing when it should. A technician fixes the binding first, then resets the force and travel limits. See rollers and hinges for the usual cause.
Wiring failures, a bad logic board or sensors that are simply worn out are also things a technician can sort out quickly. If your opener is old, read opener repair before spending much on it.
Don't Leave It Broken
Some people bypass the sensors or just hold the button every time. Please don't. The auto reverse is the main safety feature on a garage door.
If the checks above don't fix it, send the form or call (919) 555-0136. A remote that quit is a different problem, covered on the remotes and keypads page.
