When the garage door sensors won't let the door close

The two little boxes low on the track are photo eyes. A beam runs between them; break it while the door is closing and the opener throws the door back up. They've been mandatory since 1993 because they stop doors landing on people, and they're built to trip easily.

Which means the flashing-light refusal is the opener being careful, not failing. Something is in the beam, or the eyes are out of line, or one has lost power. Find which.

In this order, because that's the order the faults come in.

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 lensesWipe the lenses. Grit and exhaust film build up quietly and the receiver loses the beam in low light.
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.

If the eyes are fine and the door still comes back up: at the floor, it's the travel limit; part-way, with a heavy door, it's the spring and the force setting. One is a tweak, the other is a spring replacement and the opener should rest until then.

In Lewisville winters a door that only reverses on cold mornings is the force setting reacting to a stiff door; a balance check settles it.

When an eye has genuinely failed, the pair is replaced together. It's twenty minutes with the right set, and the right set depends on the brand and the generation printed on the motor housing.

Bad wiring is replaced properly rather than patched, so the same call doesn't recur next winter.

A last detail: the brackets. The eyes should be level with each other and a few inches off the slab. A bracket that has taken a hit from a bumper or a bin never quite holds, and an eye that keeps needing realignment is telling you the bracket has gone. New bracket, problem gone.

The technician reads the LEDs, clears and cleans, realigns, follows the wire, and replaces the pair only if one is actually dead. Then a balance check on the door, because that's the second fault we find most. Free estimate anywhere in Denton County.

It's normally a quick call; when it isn't, the spring was the real story.

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.

One call, a two-hour window, and a call ahead from the technician. That's the routine across Lewisville, Castle Hills and Flower Mound.

Free estimate. Throughout Denton County, including Old Town, Castle Hills, Vista Ridge, Flower Mound, Carrollton, Coppell, Highland Village.