Garage Door Won’t Close? Sensor Troubleshooting Guide
You press the button, the door starts down, then stops and goes back up, or it won’t move at all and a light on the opener is blinking. Here’s exactly what to check, in the order we’d check it.
Why the Door Refuses to Close
Every opener sold in the U.S. today has a safety system built in. Two small sensors, called photo-eyes, sit on either side of the door opening near the floor, and they shoot an invisible beam across the doorway. If anything breaks that beam, the opener assumes something (a child, a pet, a bicycle) is in the way and won’t let the door come down. So when the door reverses or refuses to close, the opener is usually doing its job. The real question is why it thinks something is in the way.
Step-by-Step: What to Check
The Coastal Factor: Why This Happens More Here
Salt-laden humidity is hard on the tiny electrical connections in sensor wiring. Corrosion at a wire splice or terminal can cause an intermittent connection, which is why some customers tell us the door “works sometimes” and quits other times. Grime on the lenses builds faster here too. If you’re seeing sensor trouble more than once or twice a year, it’s often an early sign of moisture getting into your opener’s electronics. We cover that broader pattern in our coastal corrosion guide.
Other Things That Trip Up Sensors
- Direct sunlight. Low morning or evening sun shining straight into the receiving eye can wash out the beam. If your door acts up at the same time of day, this may be why. Shading the sensor with a small cardboard or PVC hood often helps.
- Landscaping and yard work. A mower, trimmer, or ladder leaned against the wall can nudge a sensor bracket just enough to throw off the alignment.
- Storm vibration and debris. After a big wind event, sensors are one of the first things to end up slightly off. See our post-storm checklist.
- A bent bracket. If the bracket itself is bent, the sensor won’t hold alignment no matter how carefully you set it.
What Not to Do
When It’s Not the Sensors
If both sensors look aligned and clean and the door still won’t close, the cause may be something else entirely:
- A wiring fault in the sensor cable that isn’t visible
- A failing logic board in the opener (moisture damage is a common cause on the coast)
- A door that’s out of balance because of a weakening spring, which can make the opener think it’s meeting resistance
- A track obstruction or a bent section of track
Each of these needs a proper diagnosis, and that’s where a technician earns their fee. See our sensor repair page and opener repair page for what those repairs involve.
What a Professional Sensor Repair Includes
When we come out, we clean and realign the sensors, test the wiring end to end, and replace parts that have failed. Then we test the safety reversal on purpose, breaking the beam mid-close to confirm the door stops and reverses the way it’s supposed to. Most sensor calls fall within our standard opener repair range of $100-220. You’ll get a written price before we start, as always. Our cost guide has the full breakdown.
Frequently Asked Questions
That’s the safety reversal working. The opener thinks the beam between the sensors was broken, usually because of dirty lenses, misalignment, or an obstruction. Cleaning and realigning the sensors fixes it most of the time.
A blinking light on the opener usually signals a safety-sensor problem, though some models use a specific number of flashes to indicate different faults. Check your opener’s manual for the code that matches your model, and start with the sensor checks above.
We strongly advise against it. The sensors are the main protection against the door closing on a person or pet, and overriding them removes that protection.
Wind, debris, or vibration can knock a sensor bracket out of alignment, and rain or humidity can affect wiring. Check alignment and clean the lenses first.
Typically $100-220, depending on whether it’s a simple realignment or requires wiring or sensor replacement.
Still Won’t Close?
Call (854) 248-1833 for same-day service and a written price before we start.
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