Garage Door Sensor Repair in Collin County, TX

What the safety sensors do

The two small boxes near the floor on either side of your garage door are photo-eye safety sensors. One sends an invisible infrared beam across the opening and the other receives it. If anything breaks the beam while the door is closing, the opener stops and reverses.

They are not optional. The federal standard for residential openers, 16 CFR Part 1211, requires openers to have a secondary means of entrapment protection in addition to built-in reversing, and photo eyes are the usual choice (section 1211.6). Under section 1211.8, the opener checks that the device is present and working at least once on every close, and will not close the door normally if it finds a fault. That monitoring is why a door with a sensor problem will open but refuses to close from the remote.

How high should they be?

The CPSC safety sheet says electric eyes should be installed 4 to 6 inches above the floor. Chamberlain's support pages describe the sensors as no higher than 6 inches above the garage floor, and Genie's guidance says not to mount them more than 6 inches off the floor. The federal test in section 1211.11 checks that the sensors detect an object only 6 inches high placed on the floor. Sensors moved higher to keep them out of the way can miss a small child or a pet lying in the doorway.

Signs of a sensor problem

• The door starts to close, then stops and goes back up.
• The opener lights flash and the door will not close from the remote or keypad.
• The door closes only if you hold the wall button down (some openers allow this as an override, but Chamberlain says the feature is not available on its openers or replacement logic boards made after February 3, 2022).
• The problem appears at a certain time of day and disappears later.
• One of the small sensor lights is off, flickering or blinking.

What you can check yourself

These steps are safe for most homeowners because they do not involve springs, cables or the door hardware.

1. Clear the beam. Look for anything in the doorway near the floor: a trash can, a broom, a bike wheel, leaves or a spider web over a lens.
2. Clean the lenses. Wipe both with a soft dry cloth. Dust and dried water spots can be enough to weaken the beam.
3. Read the sensor lights. On Chamberlain and LiftMaster systems, the sending sensor has an amber light and the receiving sensor has a green light. If the amber light is steady but the green one is off or flickering, the sensors are usually misaligned or blocked. Other brands use different colors, so check your manual.
4. Realign gently. Sensors on the track brackets get knocked by cars, bikes and lawn equipment. Chamberlain's instructions are to loosen the wing nut on the receiving sensor, point it straight at the sending sensor until its light glows steadily, and tighten it again.
5. Look at the wires. Follow the thin wires from each sensor back toward the opener. Staples driven through the wire, chewed insulation or a loose connection at the opener can all cause faults. Chamberlain notes that if neither sensor lights up, there may be an open or shorted wire.
6. Count the flashes. Many openers flash a code when the sensors fail. Chamberlain's diagnostic code guide lists a code for blocked or misaligned sensors. Write down what you see; it helps a technician.

Sun glare and west-facing garages

Low afternoon sun can shine straight into the receiving sensor. Genie explains that sunlight carries infrared light, just as the sensors do, and strong sun into the receiver can drown out the beam from the sender. The result is a door that will not close in the late afternoon and then works fine after sunset.

If your garage faces west, expect it on sunny afternoons; an east-facing door can see the same thing in the early morning. The manufacturer fixes are simple:

• Swap sides. Chamberlain's page on sunlight interference recommends switching the sending and receiving sensors to opposite sides of the door so the receiver is in the shade. It notes that this can simply move the problem to another time of day.
• Shade the receiver. Sun shields sold for this purpose, or a small shade, keep direct light off the receiving lens.
• Upgrade older sensors. Genie mentions newer sensors with a lens cover designed to reduce false signals.

Swapping sides involves re-running wires, so if you are not comfortable with low-voltage wiring, a technician can do it quickly.

The monthly reversal test

Two tests are worth doing once a month, and after any repair or adjustment.

Photo-eye test. With the door fully open, start it closing and pass an object, such as a broom handle, through the beam near the floor. The door should stop and reverse. Do not use your body or anyone else's.

Contact reversal test. With the door open, lay a 2x4 flat on the floor in the middle of the doorway and close the door. It must reverse when it hits the board. This is the test written into the federal owner instructions in 16 CFR 1211.16: the door must reverse on contact with a 1 1/2 inch object, or a 2 by 4 board laid flat. The CPSC recommends the same 2x4 test.

You may see advice to use a roll of paper towels instead. DASMA, the garage door industry association, addresses this directly in Paper Towels vs. 2x4s: a paper towel roll might show that the door reverses, but it might not compress to 1 1/2 inches, so it does not prove the door reverses at the right height. DASMA recommends a 2x4 laid flat and testing monthly.

If the door fails the 2x4 test, the CPSC advises disengaging the opener until it is adjusted, repaired or replaced. Use the door by hand in the meantime, as described in how to open a garage door manually.

When you need a technician

Call a local garage door technician if:

• The sensors are aligned and clean but the lights still will not stay steady.
• The wiring is damaged inside a wall or ceiling.
• A sensor bracket is bent or the track it mounts on is damaged.
• The door fails the 2x4 test even with good sensors, which points to travel or force settings or the door itself.
• The opener is old enough that it has no sensors at all. The CPSC notes photo eyes or equivalent protection have been required since 1993. See opener repair.

What to ask a technician

• Is the fault in the sensors, the wiring or the opener's logic board?
• Are replacement sensors the same brand, and are they compatible with my opener?
• Can you move the receiver to the shaded side if sun is the cause?
• Will you do the 2x4 test and the photo-eye test before you leave?
• What does the visit cost if the fix turns out to be alignment only?

For more on picking someone reputable, see choosing a technician.