6 min read
If your garage door starts to close and then reverses — or the opener light blinks and nothing happens — the safety sensors are the first thing to check. These two small “photo eyes” near the bottom of the tracks are required on every modern opener, and they are designed to stop the door the moment anything crosses their path. When they are dirty, bumped or out of line, the opener thinks something is in the way and refuses to close. The good news: most sensor problems take minutes to fix.
How garage door safety sensors work
One sensor sends an invisible infrared beam across the opening, about six inches above the floor. The other sensor receives it. As long as the beam is unbroken, the opener is allowed to close the door. If a child, pet, car bumper or even a leaf breaks the beam, the opener immediately stops and reverses.
Each sensor has a small LED. Usually the sending sensor glows steadily, and the receiving sensor glows only when it “sees” the beam. A receiving light that is off or flickering is your biggest clue.
The 6 most common causes
- Misalignment — a sensor was bumped by a bike, trash can or broom and now points slightly away from its partner.
- Dirty lenses — dust, cobwebs, pollen and road spray build up on the lenses, especially in a damp Pacific Northwest garage.
- Something in the beam — a box, rake, shoe or even a hanging strap can block the path.
- Direct sunlight — low morning or evening sun shining straight into the receiving sensor can overwhelm it.
- Loose or damaged wiring — staples pulled loose, a chewed wire or a corroded connection at the sensor or the opener.
- A failing sensor — after years of use, the sensor itself can wear out.
Simple fixes you can safely try
Start by clearing anything near the bottom of the door opening. Then wipe both lenses gently with a soft, dry cloth. Check the LEDs: if the receiving light is off, loosen the sensor’s wing nut, slowly adjust it until the light comes on and stays steady, and retighten. Both sensors should sit at the same height and point straight at each other.
If sunlight is the problem, it usually only happens at certain times of day. Swapping the sending and receiving sensors between sides, or adding a small shade, often solves it. Finally, follow the thin wires from each sensor up to the opener and look for obvious damage or loose staples.
When to call a professional
If the lights still won’t go steady after cleaning and aligning, the problem is usually wiring, a failed sensor or the opener’s logic board. Those are quick repairs for a technician, and we’ll also run a full safety-reverse test so you know the door will stop for a child or pet. Never disconnect or bypass the sensors to make the door close — they exist to prevent serious injuries.
Frequently Asked Questions
Can I close my garage door if the sensors aren’t working?
On most openers you can press and hold the wall button until the door is fully closed, which overrides the sensors temporarily. Stay in the garage and watch the door the whole time, and get the sensors fixed as soon as possible.
Why does my garage door close fine at night but not during the day?
That is a classic sign of sunlight hitting the receiving sensor. Swapping the sensors between sides or shading the receiver usually fixes it.
Are garage door safety sensors required?
Yes. Federal safety standards have required an entrapment-protection system, such as photo-eye sensors, on residential garage door openers since the early 1990s.