Stuck right nowGarage doors
Garage door won't close? Sensors, sun and other causes
A garage door that won't close at night is a security problem as well as a nuisance. Here is how to find the cause, starting with the sensors.
A door that won't close is more than a nuisance. Left open overnight, it's an open invitation to anything in the garage and often to the house. So here is the order to check, and how to secure the door tonight if you can't fix it.
It closes if I hold the button. What does that mean?
That's the clue that points straight at the sensors. On many openers, holding the wall button down overrides the safety sensors, so the door closes even though the opener thinks something is in the way. LiftMaster's guidance is that if the door closes only while you hold the button, the safety sensor system needs troubleshooting (LiftMaster).
Not every opener allows this override, so check your manual. Where it works, use it only while you watch the door all the way down, with nobody near it.
That points at the safety sensors. Use the hold override only while you watch the door all the way down.
How do I check the sensor lenses and alignment?
The sensors sit on the door tracks just above the floor; LiftMaster's manuals put the beam no higher than 6 inches (15 cm). One sends an invisible beam across the opening and the other receives it. On LiftMaster and Chamberlain openers, the sending sensor has an amber light and the receiving one a green light.
- Look at the lights. Both should be steady. A green light that is off, dim or flickering means the receiver isn't getting the beam.
- Clear the path. Boots, a recycling bin, a snow shovel or a cobweb across the lens is enough to break the beam.
- Clean both lenses with a soft dry cloth. Road salt spray and garage grime build up over a winter.
- Realign. LiftMaster's advice is to loosen the wing nut, point the lenses at each other, and tighten it again once the green light glows steadily.
- Check the wires running up the wall from each sensor for staples through the cable, chewed insulation or loose connections.
On LiftMaster and Chamberlain openers, the main lights flashing ten times as the door reverses is the sensor fault code. Other makes have their own codes, listed in the manual.
Clear the path, wipe both lenses, and realign until the green light glows steadily.
Can low winter sun really blind a sensor?
Yes, and in Winnipeg it's a seasonal problem. In winter the sun sits low in the sky for much of the day, and a garage facing it can get direct light straight down the sensor line for an hour or two.
Chamberlain explains that sunlight shining into the receiving sensor can block the infrared light from the sending sensor (Chamberlain). The symptom is a door that opens fine but won't close at the same time each day.
Two fixes:
- Swap the sensors to opposite sides of the door, so the receiver faces away from the sun. Watch it at morning and evening afterwards, since the problem can move to a different time of day.
- Shade the receiver. Chamberlain sells a sensor sun shield for this; check it suits your opener model first.
Low sun can blind the receiver. Swap the sensors to opposite sides or shade the receiver.
It closes, touches the floor and bounces back up
If the door reaches the floor and reverses, and the lights don't flash, the sensors aren't the problem. The opener's close settings or the door itself are:
| What you see | Likely cause |
|---|---|
| Reverses just as it touches the floor | Close travel limit set too far, so the opener thinks it hit something |
| Reverses partway down, no flashing | Door binding, stiff from cold, or force set too low for a stiffer door |
| Stops a few inches short | Close travel limit set too short, or ice on the floor |
| Rubs, jerks or stops at the same spot | Bent track, damaged roller or a loose hinge |
Travel and force can be adjusted, following your manual. But LiftMaster warns never to use force adjustments to make up for a binding or sticking door; free the door first. After any adjustment, test the safety reverse with a 2x4 laid flat under the door. The door must reverse when it touches it.
If the opener won't run at all, rather than running and reversing, that's a different problem; see garage door opener not working.
Free a binding door before changing force settings, and test the safety reverse with a 2x4 after any adjustment.
Could ice and snow at the threshold be the problem?
In January, often. Packed snow or a ridge of ice along the floor stops the door before it reaches its close position, and the opener reads that as an obstruction and reverses. A bottom seal that froze to the floor overnight and tore can also hang down and catch.
Chip the ice away from the floor, not from the rubber, dry the threshold and keep it swept. Frozen seals and the rest of the cold-weather causes are covered in garage door won't open in cold weather.
Chip the ice from the floor, not the rubber, then dry the threshold and keep it swept.
It won't close tonight. How do I secure it safely?
Don't leave it propped open overnight, and don't leave the house unlocked behind it.
- Try the hold-to-close override if your opener has it, watching the door all the way down.
- Once it's closed, lock it. Many doors have a slide lock on the inside. Engage it, and if you're worried about the opener reopening the door, unplug the opener until it's fixed.
- Lock the door between the garage and the house, and the garage side door.
- If the door won't close at all, don't pull the release with the door open. Chamberlain advises using the emergency release only when the door is fully closed, because a door with weak springs can fall without warning.
Garage doors are a 24/7 service, so a door stuck open at night is something we can come out for. And if the night is the worry, our guide to garage break in prevention covers the side door, the release cord and remotes left in cars.
If you've checked the sensors and the door still won't close, or it's reversing for no reason you can find, book garage door opener repair.
This one is a call, not a fix.
Don't pull the release with the door open. A door stuck open at night is something we can come out for.
Garage door opener repairQuestions people ask
- Why does my garage door only close when I hold the button?
- Holding the wall button overrides the safety sensors on many openers. If the door closes that way but not from the remote, the sensors are blocked, dirty, misaligned or wired badly. Use the override only while you watch the door, and fix the sensors soon.
- Can sunlight affect garage door sensors?
- Yes. Chamberlain explains that sunlight shining into the receiving sensor can drown out the beam from the sending sensor, so the opener thinks something is in the way. It often happens at the same time each day, when the sun is low.
- Why does my garage door go back up?
- If the opener's lights flash as it reverses, the sensors are the usual cause. If it reverses without flashing after touching the floor, the close travel or force setting may be off, or ice, a bent track or a stiff door may be stopping it.
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