Four times out of five this is a safety sensor doing exactly what it was designed to do. The gate is not broken so much as refusing, and the thing it is refusing about is usually visible from where you are standing.
Also described as “gate won’t close”, “gate won't close”, “gate opens but won’t close”, “gate opens but won't close”.
We start at the photo-eyes, because that is where this fault almost always is
Sensors get realigned or replaced — never bypassed to make a gate close
An open gate is an unsecured property, so we treat this one as urgent
Security risk
The property is not secured while the gate stands open. This is the one fault on this site we treat as urgent by default, whatever the cause turns out to be.
Check these first — before you call anyone
Some causes of gate won’t close you can resolve yourself in minutes. We would rather you found one than paid us to.
1
Look along the photo-eye beam
Find the two sensor housings facing each other across the opening, usually low down on the posts. Check for anything crossing the beam — a bin, a parked bumper, a grown shrub, a spider web across a lens. This is the single most productive check on this page.
2
Clean both lenses
A soft dry cloth on both the transmitter and the receiver. Pollen, dust and mud accumulate, and in this region spiders build across the gap between the housings remarkably quickly. Many gates close normally straight afterwards.
3
Check whether the fault has a pattern
Does it only happen on foggy mornings, or only in late afternoon sun? A time-of-day pattern points squarely at the photo-eyes and tells us which one — low sun behind a receiver overwhelms it, and condensation scatters the beam. Tell us the pattern and we will arrive knowing the answer.
4
Watch what the gate does when you command it
Does it not move at all, or start closing and stop? Not moving points at a safety input blocking the command. Starting and stopping points at a limit, an obstruction, or obstruction-force detection. Two different diagnoses.
What not to do
Do not disconnect, tape over, or bypass a photo-eye to make the gate close. It is the only thing preventing the gate closing on a car, a pet or a child, and disabling it is both dangerous and a code violation.
Do not increase the obstruction-force setting to push the gate past whatever is stopping it.
Do not leave the gate standing open overnight without telling us — we would rather secure it than leave the property open.
Do not spray lubricant on photo-eye lenses. It attracts dust and makes the problem permanent.
Checked all that and it is still gate won’t close?
A gate that will not close is usually obeying its safety system
Powered gates are required to detect obstructions before and during closing. In practice that means photo-eyes — an infrared beam across the opening — and often an edge sensor on the leading edge of the gate. If either believes something is in the way, the operator will not close, and many will not even attempt it.
That is the correct behaviour. A closing gate is hundreds of pounds moving under power, and the sensor is the only thing standing between it and whatever is in the gap. So the question on this page is almost never "how do I make it close" — it is "what does the sensor think it can see".
Why sensors see things that are not there
A photo-eye is a transmitter and a receiver aimed at each other, often across twelve feet or more. Anything that breaks or scatters that beam reads as an obstruction: a spider web across the lens, condensation on a foggy morning, a bump from a car door that knocked the housing a few degrees out of alignment, dust and pollen build-up, or direct low sun flooding the receiver.
The giveaway is a pattern. A gate that will not close only on foggy mornings, or only in late afternoon when the sun is low behind the receiver, is telling you precisely what is wrong. A gate that will not close at any time of day has usually suffered actual misalignment or a failed sensor.
What causes it, most likely first
Each of these looks different at the gate. The “how to tell” line is what separates it from the one above.
Photo-eye blocked, dirty or misaligned
most commonYou can often fix this
How to tell
Look along the beam path for anything crossing it, then look at the lenses themselves — spider webs, dust and mud are the usual culprits. Most photo-eyes have an indicator LED that changes state when the beam is broken; if it shows blocked with nothing in the way, it is dirty or out of alignment.
The fix
Cleaning the lenses and realigning the housings. Frequently a five-minute job, and one a careful owner can often do themselves.
Failed photo-eye or damaged sensor wiring
common
How to tell
Lenses are clean and aligned, and the sensor still reports an obstruction — or shows no power at all. Wiring to gate-mounted sensors flexes every single cycle and eventually fractures, usually where it leaves the housing.
The fix
Sensor or cable replacement. Small parts, and worth doing properly rather than repeatedly realigning a sensor whose cable is the actual fault.
Close limit switch out of adjustment
common
How to tell
The gate starts closing and stops short of the post, or does not attempt to close because it believes it already is. Distinguished from a sensor fault by the gate actually moving before it stops.
The fix
Re-setting the close limit and re-learning the travel. If the gate has sagged, the limit is a symptom and the sag needs fixing too.
Obstruction in the closing path
commonYou can often fix this
How to tell
Walk the closing path with the operator released. Gravel washed into a slide gate’s track, an overgrown shrub, a stone, or the gate grounding on a driveway that has heaved will all stop it.
The fix
Clearing the obstruction, and addressing the reason it is there. A slide gate track that fills with grit after every storm needs a drainage answer, not a monthly sweep.
Edge sensor triggered or failed
less common
How to tell
An edge sensor is a pressure-sensitive strip on the leading edge of the gate. A damaged one, or one whose cable has fractured, reports permanent contact — so the operator behaves as though the gate is already touching something.
The fix
Edge sensor replacement. These take physical abuse by design, so they are a genuine wear item on a busy gate.
Timer-to-close disabled or set to hold open
less common
How to tell
The gate closes normally when commanded but never closes on its own, and always has to be told. That is a configuration setting, not a fault. Common after a board replacement, when the setting was not restored.
The fix
Enabling and setting the timer-to-close at the board. A configuration change rather than a part.
Repair, or replace?
This is the most fixable fault on this site and one of the cheapest. The overwhelming majority are photo-eyes — dirty, misaligned, or wired through a cable that has finally fractured — and all of those are small parts and short visits. Genuine operator failure is well down the list of causes.
Usually a repair
Photo-eye cleaning, realignment and replacement
Sensor cabling that has fatigued at the flex point
Close limit adjustment and travel re-learning
Obstructions and the drainage or landscaping causing them
Edge sensors and timer-to-close configuration
Sometimes a replacement
A sensor type no longer manufactured, where a current equivalent is the sensible upgrade
An installation whose safety devices predate current standards and cannot be made compliant as they are
Why this happens in Dallas–Fort Worth
Fog, low sun and Texas spiders
Three local conditions produce most of the photo-eye faults we see. Morning fog near the lakes — Lewisville, Ray Hubbard, Grapevine — puts condensation on lenses and scatters the beam, which is why lakeside gates classically refuse to close early and behave perfectly by lunchtime.
Low sun is the second: a receiver facing west gets flooded in late afternoon and reads a fault. The third is simply that this region has a long warm season and spiders build webs across the gap between two sensor housings faster than anyone expects. None of these is an operator fault, and all of them get misdiagnosed as one.
Storm grit and slide gate tracks
Heavy DFW downpours wash grit and gravel into slide gate tracks, and on exposed sites the wind delivers more. A track with debris in it stops the gate short of closed, and the operator reads the resistance as an obstruction — correctly. The gate is not faulty and neither is the sensor; the track needs clearing and, if it happens repeatedly, the drainage around it needs looking at.
My gate opens but will not close. What is the most likely cause?
A photo-eye — the infrared safety beam across the opening. Something is breaking it or the sensors are dirty or knocked out of alignment. Check the beam path and clean both lenses before anything else; that resolves a large share of these calls at no cost.
Can I just disconnect the sensor so the gate closes?
No, and we will not do it either. That sensor is what stops several hundred pounds of gate closing on a vehicle, a pet or a child, and disabling it is both dangerous and contrary to the safety standard gates are built to. If a sensor is faulty, the fix is to repair or replace it.
It only fails to close in the morning. Why?
Almost certainly condensation on the photo-eye lenses. Moisture scatters the infrared beam, the operator reads an obstruction, and once the sun burns the fog off it behaves perfectly. It is genuinely fixable — repositioning, hooding, or a sensor type that tolerates moisture — and it does not mean the gate needs replacing.
The gate starts closing then stops and reopens. Is that the same fault?
Related but distinct. Reversing mid-travel usually means obstruction detection triggered by real resistance — a fouled track, a dropped hinge, or a force setting that no longer matches a gate that has aged. See our page on a gate that reverses when closing.
How quickly can someone come out? The gate is stuck open.
We treat an open gate as urgent because the property is not secured, and we aim to get someone out the same day. If the fix needs a part we do not carry, we will secure the entrance in a safe state rather than leave it standing open indefinitely.
Tell us what your gate is doing
Include what you found in the checks above — where it stops, what you heard, whether it moves by hand. It genuinely shortens the visit, and it means we arrive with the right part more often.
We answer the phone 24/7. If you are stuck, call and we will talk you through the manual release before anyone arrives. See what counts as a gate emergency.
