Safety sensors are the two small photo eyes near the bottom of the door tracks. If their beam is blocked, out of line or the wire is cut, the opener refuses to close the door or sends it back up. We realign the eyes, repair the wiring or fit a matched new pair, then test the safety reverse before we leave.
What you get
- Both photo eyes checked for alignment, clean lenses, solid brackets and power at the opener
- Sensor wire traced from each eye to the opener head, with cuts, chewed spots and staple damage repaired
- A new pair matched to your opener when the old eyes have failed, wired and aligned
- Eyes set 4 to 6 inches above the floor, where the beam catches a small child or a pet
- Safety reverse tested with a board on the floor and an object through the beam before we leave
What the safety sensors do
Every garage door opener sold in the United States since 1993 has to protect against trapping a person under a closing door. The UL 325 standard covers it, and on almost every home opener the answer is a pair of photo-eye safety sensors, one on each side of the opening. The U.S. Consumer Product Safety Commission advises mounting them 4 to 6 inches above the floor, so the beam sits no higher than about six inches.
One eye sends an invisible beam across the doorway and the other receives it. If a child, a dog or a bike breaks the beam while the door is coming down, the opener sends the door back up. When it cannot see the beam at all, it will not close from the remote or the keypad.
Some older garages, including a few in Vista, still run openers from before 1993 with no photo eyes at all. Those are worth replacing.
Why the door will not close: the usual causes
Most sensor faults come down to a short list, and a blinking light on one eye usually points at one of them. The blinking sensor light page explains the lights.
- Out of line. A bumped bracket or a loose wing nut lets an eye droop until it no longer points at its partner.
- Something in the beam. A broom, a box, a cobweb or a dusty lens is enough to block it.
- A damaged wire. A staple, a new shelf or a rodent can break the thin wire to the opener, and homes backing onto canyons, as many in Rancho Peñasquitos do, see more of the last.
- Sun glare. Low sun shining into the receiving eye can blind it, so a west-facing door may refuse to close only in the late afternoon. The door will not close page covers that pattern and its fixes.
- A failed eye. Sensors age, and an eye can quit after water or a hard knock.
Need your garage door sensors fixed today?
Call or text with your address, single or double door, and what the door is doing. The price is firm before the truck leaves the yard.
What you can safely check first
Safety first: do not touch the springs, cables, cable drums or bottom brackets, and if the door is crooked or a spring is broken, do not run the opener. Sensor checks are safe because the eyes run on low voltage.
- Look at both eyes. On most pairs, a steady light on each means the beam is getting through, and a blinking or dark light means misalignment, a blocked beam or a wiring fault.
- Clear the doorway and wipe both lenses with a soft cloth.
- If one eye points at the floor, turn it gently back toward the other until its light goes steady.
- Follow each wire toward the opener and look for staples through it, chewed spots or a loose connection.
If the lights will not go steady after that, leave the brackets and wiring to us and book the repair.
Realign, rewire or replace: how we decide
We start with the simplest fix that makes the door safe, and test after each step.
- Realign when both lights come on once the eyes face each other and stay steady while the door runs. Brackets that keep drooping get tightened or replaced.
- Rewire when an eye stays dark even though the opener is sending power to the sensor terminals. We splice or replace the run and route it where staples, shelves and car doors will not reach it.
- Replace when an eye stays dark or flickers with good wire and good alignment, or the lens or housing is cracked. We fit a pair matched to your LiftMaster, Genie or other opener, because sensors from one opener family usually do not work on another.
How we diagnose a sensor call
We start at the eyes: lights, lenses, brackets and alignment. Then we check that the opener is sending power to the sensor terminals and trace the wire run for breaks, so a dark eye is never blamed on the eye before the wire is ruled out.
Next we run the door several times and watch where it stops. A door that reverses partway with nothing in the way often has an eye that flickers as the track shakes, or a wire that loses contact. A door that touches the floor and goes back up, or reverses at the same spot every time, points away from the sensors to the close limit, the force setting or a binding roller, and we move on to the opener or the door itself.
Safety Sensor Repair: common questions
How do you align garage door safety sensors?
We loosen the bracket or wing nut on the eye that has drooped, turn it until it points straight at its partner, and tighten it when its light goes steady. Then we check that both eyes sit at the same height, 4 to 6 inches above the floor, and run the door to confirm it closes and reverses when the beam is blocked. Brackets that keep slipping get replaced.
How long does safety sensor replacement take?
Usually one visit. We carry safety sensors for the common opener brands, so a matched pair can be fitted, wired and aligned on the spot. The time depends mostly on the wire: an intact run is reused, while a run that is chewed, stapled through or buried behind shelving gets replaced and rerouted. The safety reverse test at the end is the same either way.
Why should I not just bypass the garage door safety sensors?
Every residential opener sold in the United States since 1993 must have an entrapment-protection system under the UL 325 standard, and almost all use photo-eye sensors near the floor. The opener is designed not to close from the remote without them. Bypassing them, taping them together or mounting them high removes the protection that keeps a closing door from trapping a child or a pet.
Do I need to replace both garage door sensors if one is bad?
Usually, yes. The sending and receiving eyes work as a pair, replacement sensors are generally sold as a pair, and the eye that still works is as old as the one that failed. We rule out alignment and wiring first, since those cause most sensor problems. If an eye has truly failed, we fit a new pair made for your opener brand.
How high should garage door safety sensors be mounted?
The U.S. Consumer Product Safety Commission advises 4 to 6 inches above the floor, so the beam is no higher than about six inches. At that height it catches a small child or a pet lying in the doorway. Both eyes should sit at the same height and face each other squarely. Sensors moved higher to dodge sun glare or bumps defeat their purpose.
The FAQ page has more answers. Not sure which part failed? Send a photo and we will name it.
Where we do this
We cover all of San Diego County, same day in most cases. Some of the places we work:
Related guides
- Garage Door Won't Open or Close? A Safe Checklist: Garage door stuck? Safe checks in order: power, wall control lock, remote battery, sensor lights and release cord, plus which symptom needs which repair.
- Repair or Replace Your Garage Door Opener?: When a garage door opener is worth repairing and when to replace it: drive gear, logic board, rolling code, California battery backup law and drive types.
- Garage Door Maintenance Checklist: Monthly, Twice a Year, Yearly: A garage door maintenance checklist: monthly safety tests, twice-yearly cleaning and lubrication, a yearly technician visit, and inland versus coastal.
Ready to get the door moving again?
One call or text gets you a straight answer and a firm price before the truck rolls. Mon to Sat 7am to 7pm.