Why won't my garage door close? (It goes down, then back up)
Short answer
A garage door that starts closing and reverses is almost always a safety sensor problem: the two photo eyes near the floor are misaligned, dirty, blocked or blinded by sunlight. Clean the lenses, check both lights are solid, and clear the path. If it still reverses, it may be a wiring, force-setting or track issue. Send us a short video by WhatsApp or text and we reply with a quote.
What do the safety sensors do?
Every residential opener made for sale in the US since January 1, 1993 must have a secondary entrapment protection device under federal law (16 CFR 1211). On most homes that’s a pair of photo eyes mounted on each side of the door, a few inches above the floor. One sends an invisible beam, the other receives it. If the beam is broken while the door is closing, the opener reverses the door. When the eyes can’t see each other, the opener treats it as an obstruction every time.
What can I check in 5 minutes?
- Look at the lights on both sensors. Most brands show a solid light on each eye when aligned. A blinking or off light on one side points to misalignment or wiring.
- Clean both lenses with a soft dry cloth. Dust, spider webs and pollen are enough to block the beam.
- Clear the path. Trash cans, boxes, a hose, tall grass at the threshold, or a sagging weatherstrip can break the beam.
- Realign. Loosen the wing nut, aim the eyes straight at each other at the same height, and tighten until both lights are solid. Most opener manuals say to mount them no higher than about 6 inches above the floor.
- Check the low-voltage wires running up the wall to the opener. Staples through the wire, chewed insulation or a loose terminal cause intermittent reversing.
- Try in the morning or evening. If it only fails in the afternoon, sunlight is blinding one eye.
What if the sensors are fine but it still reverses?
| What you see | Likely cause | What we do |
|---|---|---|
| Sensor lights blink or go out | Bad sensor or damaged wire | Replace or rewire and realign sensors |
| Door reverses right after touching the floor | Close-force or travel limit set wrong | Reset limits and force, test auto-reverse |
| Door reverses partway down with no obstruction | Binding rollers or track, worn opener gear | Inspect track and rollers; replace worn parts such as rollers |
| Door is crooked or a roller has left the track | Off-track door | Put back on track, check cables |
| Opener light flashes a code | Opener self-diagnostic | Read the code, fix the cause |
Never raise the close force to “push through” a sticking door. That defeats the opener’s own auto-reverse and is how people and cars get hurt.
How do I test that the door is safe after a fix?
Run the monthly test the door industry recommends (DASMA TDS-351):
- Open the door.
- Lay a 2x4 flat on the floor under the center of the door.
- Close the door with the opener. It should stop and reverse when it touches the board.
- Then wave something across the photo eye beam while the door closes. It should reverse.
If either test fails, stop using the opener and get it serviced.
When should I call?
If the 5-minute checklist doesn’t fix it, WhatsApp us a short video of the door trying to close, plus a photo of both sensors, or text them to (561) 724-0724. We’ll tell you whether it’s a sensor job or something else, and you get a written quote before any work starts. If your door won’t open at all, see why a garage door won’t open.