Garage door sensor not working? Start here

Since 1993 every opener has shipped with two small eyes near the floor, one on each side of the opening. One sends a beam, the other watches for it, and the moment the beam breaks during a close the door reverses. That reflex is what keeps a door off a child or a car bumper, so it's tuned to be jumpy.

A door that won't close with a flashing light is therefore an opener doing its job on bad information, not a broken opener. The work is finding out why the eyes can't see each other.

Work down the list; most doors are closing again by the second item.

1. Clear the beamA trash can, a bike wheel, a cobweb, a leaf. Anything in the six inches above the floor between the two eyes trips them. Clear the space and try the door.
2. Clean the lensesA dry cloth on both lenses. Hail leaves a film on them, and a dull lens fails at dusk first.
3. Check the alignmentEach eye sits in a bracket that bends easily. If one LED is flickering, loosen its wing nut, tilt the eye until the light goes steady, then tighten. A string pulled taut between the two brackets shows whether they're level.
4. Look for sunLate afternoon sun straight into the receiving eye blinds it. If the door only misbehaves at one time of day, that's the cause. A short cardboard hood over the eye, or swapping the two sensors so the receiver faces away from the sun, fixes it.
5. Follow the wireRun a hand along the thin sensor wire from each eye up to the opener. Look for a staple that has cut through the insulation, a splice that has come apart, or the terminal screws on the motor unit working loose.

Steady LEDs and a clear beam but the door still reverses means the opener has a different complaint. Reversing right at the floor is the down-limit set a touch too far. Reversing part-way, with a door that's heavy to lift by hand, is a spring that has lost tension tripping the force setting. Adjust the first; stop using the opener until the second is fixed.

Cold-weather-only reversing is the same thing: North texas heat and hail, the door stiffens, the force setting trips.

Eyes do die: water in the lens, a mower strike, a board that gives up. A matched pair for Chamberlain, LiftMaster or Genie is stock on the truck and takes about twenty minutes to install and align. They don't cross brands or generations; the label on the motor unit tells us which pair.

Damaged wiring gets rerun with clips instead of staples, which is why it doesn't come back.

The brackets matter as much as the eyes. Both sensors should sit at the same height, a few inches off the floor, and a bracket that has been bent by a car bumper will keep drifting out of line however often it's reset. If the same eye needs realigning every few weeks, the bracket is the fault, and it's replaced on the visit.

Beam, lenses, alignment, wiring, in that order. A cloudy or dead eye gets a new pair. Before leaving, the technician disconnects the opener and lifts the door by hand, because reversing doors often have a spring problem hiding behind the sensor one. Free estimate across Irving and Coppell, Grand Prairie.

Short visit, usually. The long ones are the doors that were out of balance for a year.

The opener is broken. The opener is fine; it's refusing to close on what looks like an obstruction. Fix what the sensors see and the opener behaves.

Just bypass the sensors. Don't. Hold the wall button to close it tonight, and get the eyes working tomorrow. A door without working sensors is the door that comes down on something.

New sensors mean a new opener. No. Sensors are a matched pair that plugs into the existing unit. Twenty minutes.

Around Las Colinas and Coppell, Grand Prairie, one call gets you a two-hour slot and a heads-up call before the technician sets off. Nobody on a phone judges a door they can't see.

Free estimate. Throughout Dallas County, including Las Colinas, Valley Ranch, South Irving, Coppell, Grand Prairie, Farmers Branch.