Garage Door Won't Close? Work Through These Checks First

If your garage door opens without complaint but will not close — or starts down and immediately reverses — the fault is almost always in the safety system rather than anything mechanical. That is good news: several of the causes take two minutes to fix yourself.

Work through these in order. They are arranged from most common to least.

1. The photo-eye sensors

Since the early 1990s every automatic garage door has had a pair of small sensors mounted about 15 centimetres off the ground on each track. One sends an infrared beam, the other receives it. Break the beam and the door will not close — by design, because that beam is what stops a door closing on a child.

Look at both sensors. Each has a small LED.

• One LED off or flickering: they are out of alignment. Loosen the wing nut, nudge the sensor until the light is steady, and retighten.
• Both LEDs off: no power reaching them. That is a wiring or opener fault.
• Both steady: the sensors are fine, move to the next check.

Then clean both lenses with a dry cloth. Perth garages accumulate a remarkable amount of fine limestone dust, and a dusty lens scatters the beam enough to trip the sensor without ever looking dirty.

2. Something is actually in the beam

Obvious, and still the second most common cause. A wheelie bin, a bike wheel, a coiled hose, a stack of boxes that has slumped sideways overnight. Crouch down and look along the beam path at sensor height rather than standing up and glancing around.

Direct low sun into a sensor lens can also swamp the receiver. Perth’s afternoon sun through a west-facing opening does this reliably in late summer, and it usually resolves itself an hour later — which is a strong clue if the fault only happens at a particular time of day.

3. Test whether it is the sensors at all

Most openers let you hold the wall button down to close the door, deliberately overriding the photo eyes. Only do this with the doorway completely clear and in full view.

If the door closes fully while you hold the button, the mechanism is fine and the problem is definitely in the safety circuit. If it still reverses, the fault is mechanical or in the limit settings.

4. Close-force and travel limits

Openers store how far the door should travel and how much force is reasonable on the way. Both drift over time, and both get knocked out by a power interruption.

If the door touches the floor and immediately rides back up, the down-limit is set slightly too far. The opener reaches the ground, senses resistance, decides it has hit something, and reverses exactly as it should.

Most units have limit adjustment screws or a programming button on the motor head. This is adjustable at home, but adjust it too far the other way and you disable the obstruction detection that protects whoever is standing underneath. If you are not confident, leave it for someone who tests the auto-reverse afterwards.

5. Track and roller damage

If the door reverses at the same point every time rather than at the floor, look at the tracks at that height.

• A dented or pinched track binds the roller and the opener reads it as an obstruction.
• A seized roller drags instead of rolling.
• A loose bracket lets the track flex under load.

Sight along each vertical track from the ground. It should be dead straight and parallel to its partner. This one is not a DIY repair — a door that has jumped its track is a different and more urgent problem.

6. Remote and interference

If the door will not close from the remote but closes fine from the wall button, that is not a closing problem at all — it is a remote problem. Cheap LED downlights and some NBN equipment throw radio noise across the 433 MHz band that most Australian openers use.

A safety test worth doing regardless

Once your door is closing again, check the auto-reverse.

Lay a length of timber flat on the floor in the doorway, or a roll of paper towel on its side. Close the door. When it touches the obstruction it must stop and reverse within about two seconds. If it does not, the door is not safe and the close-force setting needs adjusting — this is the test that matters, not whether the door looks fine.

Do the same for the photo eyes: wave a broom handle through the beam mid-close. The door should reverse immediately.

Both tests take a minute and are worth repeating monthly. There is more in our safety checks for families.

When to stop and phone

Stop if the door is off its track, if a cable has come loose or gone slack, if there is a visible gap in the spring, or if the door is hanging crooked. Those are tension-related and are not user-serviceable.

Also stop if your garage is currently standing open and you cannot secure it. That is what a same-day service is for.

We can be there today

Most sensor and limit faults are diagnosed and fixed in under an hour. Phone us and describe what the door does — how far it travels before reversing tells us a lot before we have even left. No call-out fee, fixed price before we start, and if it turns out to be a two-minute alignment we will tell you that rather than invent a bigger job.