Garage Door Won't Close: Start With the Sensors
It opens fine, then refuses to come down or reverses partway while the opener light flashes. Usually the safety beams, and usually a five-minute check.
Quick Answer
A garage door that opens but won't close is usually being stopped by its own safety system. Two sensors near the floor send a beam across the opening; if it is blocked, dirty, knocked out of line or swamped by low sun, the opener refuses to close and its light flashes. Wipe both lenses, clear the path and check both indicator lights are steady. If the door still goes back up, the wiring or the opener's limits need a technician, and in Perth we price that before starting.
Common Causes
Beam blocked or knocked out of line
A bin, a bike or a bracket clipped by the car. The two eyes must face each other squarely, and a few millimetres of tilt is enough. Our garage door sensor fix guide covers realignment.
Dirty lenses
Driveway dust, cobwebs and grime from a garage left open all summer. A dry cloth fixes more of these than most people expect.
Low sun on the receiver
On west-facing garages, late-afternoon sun shines straight down the beam and the receiver loses its partner in the glare. The door only misbehaves at one time of day.
Damaged sensor wiring
The thin cable runs along the wall at floor level, where it gets kinked, stapled, chewed or cooked. A broken wire reads as a dark sensor, and safety beam repair covers rewiring.
Limits or force set wrong
If the opener expects the floor earlier than it arrives, or the down-force is set too low, it mistakes the seal touching concrete for an obstacle and goes back up.
A real obstruction
A stone in the track, a warped bottom seal or a stiff roller near the floor. In that case the reversal is doing exactly its job.
What You Can Check Safely
Safe to check yourself
- Wipe both lenses with a soft dry cloth and clear anything between them, cobwebs included
- Check each sensor's small light: steady on both is healthy; flickering or dark points to alignment or wiring
- Ease a knocked sensor back square by hand and try again
- Note when it fails — only in the late afternoon means sun glare, which a piece of cardboard shading the receiver will confirm
- Look along both tracks and the bottom seal for anything the door could be landing on
Do not attempt
- Do not tape, unplug or bypass the sensors; the door will then close on whatever is under it, child or car bonnet
- Do not raise the force setting to push through the resistance
- Do not keep cycling a door that keeps reversing; the drive takes the strain every time
When to Call a Technician
Call a technician straight away if any of the following apply:
- Lenses are clean, the path is clear, and the light still flashes
- One sensor light stays off however you angle it
- The sensor cable is cut, perished or chewed
- The door turns back partway down with nothing in the way
- It only closes while your finger stays on the wall button
Recommended Services
What Perth Customers Say
“Excellent customer service, guys came out within 30 mins of call (and this was after hours) and fixed the problem quickly so I could get my garage door closed and house secure. Highly recommend their service.”
Megan Holgate · Emergency Repairs
“Came out of an evening on a publuc holiday to fix my garage door that was not shutting and stuck and hanging very unsafely. Alan was prompt polite knowledgable and came within the hour. would throughly recommend.”
Melanie Moralee · Emergency Repairs
Get Help With This Problem
Prefer to call? 0422 828 800Garage stuck open tonight?
An open garage leaves the house exposed. Most openers will close while you hold the wall button in and watch the doorway. If yours will not, call us — we answer 24 hours a day and we will get the beams working, usually the same day.
Frequently Asked Questions
Go to the sensors first. Clean both lenses, clear the beam path, square up a knocked sensor and check both lights are steady. If the door now closes, that was it. If it still reverses with the light flashing, the fault is in a sensor, its cable or the opener's board. A door that turns back at the same height every time points instead to something in the track or a travel limit that has drifted.
Because the opener cannot confirm the doorway is clear. A dirty lens, a sensor a few degrees off, a broken wire or sun on the receiver all send the same message: beam not received, stay open. West-facing garages around Perth get the sun version in summer, and the giveaway is a door that behaves every morning.
Then the sensors have done their part and something else is stopping it. Where it turns back is the clue. Straight away or near the top: a board fault or a stuck safety input. Partway down: an obstruction, a binding roller or a bent track. At the floor: the down-limit or an uneven slab. We check all three on a sensor and opener call.
Hold the wall button in and keep holding. Most openers bring the door down slowly on constant pressure while you watch the opening, which is the safe way to shut the garage until it is fixed. Never tape or bridge the sensors so it closes on its own: the door is heavy enough to injure someone, and the beams are what prevents that.
Without power the opener cannot move the door either way. Pull the release cord, lower the door by hand — on healthy springs it comes down under control — and lock it with the slide bolt or key. When power returns, run the opener; most re-latch the carriage as the trolley passes. A door that will not come down by hand has a spring or cable fault.
The price follows what the beams need. Cleaning, realigning and testing is the smallest job, a new cable run is more, and a replacement pair of sensors more again. If the real fault is the opener's board, we tell you before touching it, because that is a different repair. The repair cost guide explains what moves the figure, and every sensor job ends with an auto-reverse test. There is no call-out fee.
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