A door that won’t open is inconvenient. A door that won’t close is a security problem — your garage, and often your house, is standing open. The causes are quite different from a door that won’t open, and most of them come down to a safety system doing exactly what it was designed to do.
It Starts Closing, Then Reverses
Most likely cause: the photo-eye safety sensors.
This is the single most common reason, and it’s the first thing to check. Two small sensors sit about 150mm off the floor on either side of the opening, with an invisible beam between them. Break the beam and the door reverses. It has been mandatory on Australian openers for decades.
Look at the LEDs on both sensors. One is the sender, one the receiver — typically one steady light on each, though colours vary by brand. If either is blinking, dim, or dark, the beam isn’t connecting.
What breaks it, in rough order of frequency:
- Something in the way — a bin, bike wheel, garden hose, cat. Obvious once you look.
- Dirty lenses — dust, cobwebs, spider webs. Wipe with a dry cloth.
- Knocked out of alignment — a car door or a foot catches the bracket. Loosen the wing nut, aim each sensor at the other until both lights go solid, retighten.
- Direct sunlight — late afternoon sun straight into a west-facing garage can swamp the receiver. If your door only misbehaves at a certain time of day, this is why. A small sun shield fixes it.
- Damaged wiring — the low-voltage wire runs along the wall and gets caught, stapled through, or chewed by rodents.
It Closes Fully, Then Immediately Opens Again
Most likely cause: travel limits or down-force set wrong.
The opener has learned the wrong “fully closed” position. It drives the door into the floor, senses resistance, decides it has hit something, and reverses — which is exactly what it should do.
Openers have travel-limit adjustments (how far the door moves) and force adjustments (how much resistance is normal). Both drift as the door settles and as weather changes the timber or concrete around the opening.
Adjustments are small — a quarter turn of the limit screw moves the door noticeably. Increase down travel slightly so the door stops just as it meets the floor.
Important: don’t be tempted to crank up the down-force so the door pushes through. That setting exists so the door stops if a child or pet is underneath. If a small limit adjustment doesn’t solve it, something else is wrong and the force setting is not the answer.
It Closes Part Way and Stops
Most likely cause: an obstruction in the tracks, or a track problem.
Run your eye along both vertical tracks. You’re looking for a dent, a bolt working loose, a bracket pulling away from the wall, or a section of track bent out of line. A dented track pinches the roller and the door jams at the same point every time — that repeatability is the giveaway.
Also check the rollers. Cracked, chipped or seized rollers bind rather than roll. Nylon rollers last around 10–15 years; steel ones less in Sydney’s coastal air.
If the door stops at a different point each time, it’s more likely to be the opener’s force setting or a failing motor than a track fault.
Nothing Happens When You Press Close
If the door will open but not close, and the sensors are fine, check whether the wall station has a lock function. Most modern wall buttons include a vacation or lock mode that disables the remotes and prevents closing. It’s easy to press by accident. Look for a small button or slide switch marked with a padlock.
Some openers also enter a lockout state after repeated obstruction detections. Unplug the opener for 30 seconds and plug it back in — that clears the fault memory on most brands.
It Closes Crooked or Slams
This one needs attention quickly.
A door that comes down at an angle, or drops the last section rather than settling, has a spring or cable problem. The door’s weight is being carried unevenly.
Pull the manual release and lift the door by hand to waist height, then let go. A balanced door stays put. If it drops, the springs have lost tension or a cable has slipped or frayed.
Don’t keep operating a door that closes crooked. It puts uneven load on the remaining cable and the opener, and a full failure with the door partway down is both dangerous and more expensive to fix.
What Not to Do
Two things we see go badly wrong:
Don’t disable the sensors. People occasionally bypass them by twisting the wires together to “get the door closed”. It works, and it removes the only thing stopping the door from closing on a child. If the sensors are faulty, replace them — they’re inexpensive.
Don’t wind the force up to force it shut. Same principle. If the door needs more force than normal, find out why.
Leaving It Open Overnight
If you can’t get it closed and need to secure the garage tonight: pull the manual release, lower the door by hand, then lock it. Most doors have a manual slide lock or a hasp point. If yours doesn’t and the door won’t stay down, a clamp on the track just above a roller will stop it lifting.
Re-engage the opener afterwards by pulling the release cord toward the door until it clicks.
Getting It Fixed
Sensor cleaning and alignment are reasonable to do yourself. Limit adjustments are borderline — small changes are fine, but if it doesn’t respond, stop. Anything involving springs, cables or a door that closes crooked should be left alone; those components store a lot of energy.
We cover all of Sydney and carry sensors, rollers, cables and track components on the van, so most of these are same-day fixes. Every repair comes with a fixed-price quote before we start and our 1-Year Labour Warranty.
Book a garage door repair or call 0468 688 145. If your garage is standing open right now, say so when you call and we’ll prioritise it.
