Here is a frustrating scenario: you press the button, the garage door starts to close, and then it stops and rolls right back up. Try again, same thing. The door opens fine but refuses to close. Before you assume something is broken, know that this specific behaviour usually points to one thing, the safety sensors, and it is often a quick fix. At True Fix Garage Doors, this is one of the most common calls we can help homeowners solve. Here is what is going on.
The Safety Sensors Are Doing Their Job
Modern garage door openers have a pair of small safety sensors, called photo-eyes, mounted near the floor on each side of the door. They send an invisible beam across the opening. If anything breaks that beam while the door is closing, a person, a pet, an object, the opener stops and reverses the door so it cannot close on someone. This is an important safety feature, required on openers for exactly this reason.
So when a door refuses to close and reverses, the opener usually believes the beam is blocked, whether or not anything is actually there. Understanding this is the key to the fix, and it is part of proper garage door opener service.
The Common Culprits
If your door will not close, check these sensor-related causes first.
| Cause | The fix |
|---|---|
| Something blocking the beam | Clear the path near the floor |
| Sensors knocked out of alignment | Realign so they face each other |
| Dirty sensor lenses | Gently clean the lenses |
| Sun glare on a sensor | Shade or reposition as needed |
| Loose or damaged sensor wiring | Needs professional attention |
The most common issues are a blocked path, a bumped sensor that is now misaligned, or dirty lenses. Most openers have small indicator lights on the sensors, when they are properly aligned and unobstructed, the lights are steady; when blocked or misaligned, a light usually blinks or goes out. That light is your best diagnostic clue.
The Quick Checks to Try
Start simple. Look along the floor for anything breaking the beam, even a stray object, a bit of debris, or a coiled hose, and clear it. Then check the sensors themselves: they should point directly at each other. A gentle bump from a car, a bike, or a snow shovel can knock one askew, so realign them until the indicator lights are steady. Wipe the lenses gently, since dirt, cobwebs, or frost can block the beam, a real consideration in a Calgary winter. These steps resolve the large majority of "won’t close" complaints.
When It’s Not the Sensors
If the sensors are clean, aligned, unobstructed, and their lights are steady, but the door still will not close, the issue may be elsewhere, the opener’s logic board, the wiring to the sensors, or a force or travel setting. At that point, or if the sensor wiring looks damaged, it is time for a professional. A technician can test the sensors, wiring, and opener settings and pinpoint the cause. Whatever your opener type, from a belt garage door opener to a chain drive, the safety system works the same way.
Frequently Asked Questions
Why does my garage door open but not close?
Usually the safety sensors, the photo-eyes near the floor, believe their beam is blocked or are misaligned, so the opener reverses the door to prevent closing on someone. It is a safety feature working, and it is often a quick fix.
How do I fix the sensors?
Clear anything breaking the beam near the floor, make sure the two sensors point directly at each other, and gently clean the lenses. Most sensors have indicator lights that are steady when aligned and unobstructed, which helps you confirm the fix.
Could winter weather cause this?
Yes. Frost, snow, or debris on a sensor lens can block the beam, and cold or a bump from a snow shovel can knock a sensor out of alignment. Cleaning and realigning the sensors usually solves it.
What if the sensors are fine but the door still won’t close?
Then the cause may be the opener’s control board, sensor wiring, or a force or travel setting, which need a professional to diagnose. Damaged sensor wiring also calls for a technician.
Get Your Door Closing Again
A door that won’t close is often a simple sensor fix. True Fix Garage Doors services openers and safety sensors across Calgary.
Call True Fix Garage Doors at (403) 667-9676. We serve Calgary and surrounding areas, seven days a week.
