Most doors that won't close, or that start down and pop back up, have a sensor or settings problem, not a broken door. Work through these checks in order.
1. Safety sensors: blocked, dirty, or misaligned
The photo-eye sensors are the two small units near the floor on each side of the door. If anything breaks the invisible beam between them, the opener refuses to close or reverses.
- Clear the path. Look for bins, bikes, leaves, or cobwebs in the beam.
- Clean the lenses with a soft cloth.
- Check the lights. Most sensors have an indicator light on each side. A light that's off or flickering usually means they're out of line. Gently adjust the bracket until both lights are steady.
- Check the wires for damage, such as a staple through the wire or chewed insulation.
On many openers, a flashing opener light after the door reverses is a sensor error. Your owner's manual lists the codes. More: garage door sensor light blinking
2. Sun glare
Strong, low sun hitting a sensor lens can make it think the beam is blocked. If your door only misbehaves at a certain time of day, glare is a likely cause.
3. Limit and force settings
The opener's limit setting tells it where "closed" is, and the force setting tells it how much resistance to accept before reversing. If the door:
- Reverses right after touching the floor, the close limit may be set too far.
- Stops short and leaves a gap, the limit may not be set far enough.
- Reverses partway down for no visible reason, the force setting may be too sensitive, or the door may be binding.
Adjustment steps vary a lot by model, so follow your manual or have a technician do it, and always re-test the auto-reverse feature afterward. Opener repair
4. Something in the track
Debris, a bent section of track, or a damaged roller can make the door bind, so the opener senses resistance and reverses. If a track is visibly bent or a roller has come out, stop using the door. Off-track repair
5. When reversing points to a spring problem
A door that suddenly feels heavy, closes too fast, or reverses because the opener is straining may have a broken or weak spring. Look for a gap in the spring above the door or a stretched extension spring. If you see one, stop. Broken spring repair
Securing the garage overnight
If the door is stuck open and you can't fix it tonight:
- Lock the door between the garage and the house.
- Move valuables out of sight and turn on exterior lights.
- Don't force the door down or prop it if a spring or cable might be broken.
- Request help and choose "ASAP." Say the door is stuck open.
More: garage door stuck open ยท emergency and same-day repair
Don't disable the sensors
It can be tempting to bypass a faulty sensor. Don't. The sensors and auto-reverse feature are what keep the door from closing on a child, a pet, or your car. If they're failing, have them repaired or replaced.
Frequently asked questions
Why does my garage door close only when I hold the wall button down?
On many openers, holding the wall button is a way to override a sensor fault, which is a strong sign the safety sensors are misaligned, dirty, or failing. Fix the sensors instead of relying on the override, because they're what stops the door from closing on a person or pet.
Why does my garage door reverse in the afternoon?
Low sun shining straight into one of the sensor lenses can confuse it. If the problem happens at the same time each day, try shading the sensor or ask a technician about repositioning it.