Garage Door Won't Open? How to Diagnose the Fault by Symptom

A garage door that will not open is almost always one of a short list of faults, and you can usually narrow it down from the driveway in about two minutes. Start with the cheap possibilities: a flat remote battery, a tripped socket, a manual release cord that has been pulled, something sitting across the safety sensors. After that, work by symptom, because the way a door fails tells you what has failed.

This guide covers the six symptoms we get called out to most, what causes each one, and how to tell those causes apart before anyone charges you to look at it. It also draws a hard line between what is safe for you to check and what is not, because garage door springs are the one component that genuinely injures people. We have been fitting and repairing doors across Berkshire, Oxfordshire and the Thames Valley since 2011, and this is the same order we work through when we arrive.

Start here: five checks that take two minutes

A fair number of the calls we take are solved by one of these before we ever get in the van. Work down the list in order.

1. Power to the operator. Electric doors run off a socket or a fused spur near the motor head. Check the switch is on, check the plug fuse, and check your consumer unit for a tripped breaker or RCD. Plug something else into the same socket to be sure. If the operator's courtesy light comes on when you press the wall button, power is fine and you can move on.
2. Batteries, in both handsets. The most common cause of a door that "just stopped working" is a flat remote battery, and it often looks worse than it is: handsets bought together tend to fail within weeks of each other. Try the second handset, then try the wall button.
3. The manual release cord. Almost every automated door has one, usually a cord and handle hanging from the boom, or a crank or lever on a roller door. If it has been pulled, by a child, by a bike, or during a power cut, the door is disconnected from the motor. The motor then runs happily and the door does not move.
4. Locks and obstructions. Up-and-over doors have a handle lock and side latch bars that people forget they turned. Check the tracks for grit, screws and garden debris, and check the floor in front of the bottom seal in cold weather. Forcing the operator against a locked door bends the latch bars and turns a free fix into a repair.
5. The photocell sensors. Automated doors have a pair of small sensors near the floor at each side of the opening, facing each other. A bin, a bike, a bag of compost, a spider's web or a dirty lens will stop the door closing. And if the operator cannot get a healthy signal back from both sensors, whether from a knocked bracket, a corroded wire or a lens too dirty to read, many controllers will refuse to open as well. Wipe both lenses and check the indicator lights: on most units, a steady light on both means the beam is intact.

What is safe to check, and what you must not touch

Almost everything on the list above is safe. The dangerous parts of a garage door are the ones storing the energy needed to lift it, and those parts stay loaded even when the door is shut and the power is off.

A single steel door weighs roughly 40 to 80kg. The spring is the only reason it feels light. A torsion spring on a standard single door stores enough energy to break bones and releases it in a fraction of a second if a set screw or a winding bar slips. The extension springs on older canopy up-and-over doors can whip loose with real force. The lift cables run at the same tension and will strip skin. None of these are homeowner jobs, and there is no version of the job that becomes safe with the right video.

So: look, do not touch. If you can see a gap in the spring above the door, two halves of a spring hanging either side of a bracket, a frayed or slack cable, or one side of the door sitting lower than the other, stop using the door and get someone out. Our guide on what to do with a snapped garage door spring covers that case in full.

Find the fault by symptom

Once the five quick checks are done, match what your door is actually doing to the row below, then read the matching section.

The door is completely dead

No movement, no motor noise, no lights. On a manual door, it is locked, the latch mechanism has failed, or the door has dropped in its frame and jammed. Up-and-over doors with worn lifting arms sag a little each year until the top edge catches the frame. Check the handle turns fully and the side latch bars are clear of their keeps before you apply any force to it.

On an automated door, press the wall button and watch the operator's courtesy light. If the light comes on, power is fine and you are looking at a lock mode, a jammed door or a failed control board. If nothing happens at all, you have no power: a tripped RCD, a blown plug fuse, a switched-off spur, or a failed transformer inside the head.

Worth ruling out before you conclude anything is broken: many wall consoles have a lock or holiday mode that disables the handsets, and on some systems the button itself. It is usually a slide switch or a long press on a small button on the console.

If you need the car out, pull the manual release with the door closed, then lift by hand. If it does not lift easily, stop. That is a spring or cable fault, not a power fault, and the door is now carrying its full weight. If your garage has no side door, an external emergency release is a small job well worth doing before you need it rather than after.

The door opens partway and stops

The question that splits this one open is simple: does it stop at the same point every time?

Same point every time means something physical is in the way. A bent section of track, a collapsed or worn roller, a dented panel catching, a hinge that has pulled its fixings, or debris in the track. Look carefully at the point where it stops and you will usually find it.

A different point each time is normally the operator. Force settings or travel limits drift over the years, motors lose torque as they age, and a door that has stiffened up can make the operator read ordinary friction as an obstruction.

Stops in the first foot and comes back down is usually a broken spring. The operator hits its force limit almost immediately because it is trying to lift the entire weight of the door on its own. This is the most common version of this symptom, and it peaks in winter.

To separate door from motor, use the by-hand test, but only on a door that still feels light. With the door closed, pull the manual release and lift it gently. A door in good order moves with roughly the effort of lifting a bag of shopping. If it is heavy from the first inch, stop there: the fault is in the door, and it is a spring or cable fault, which is the point at which this stops being a homeowner job. If it lifts easily, run it through its travel by hand and feel for a catch at a particular height. If it runs smoothly by hand, the fault is in the operator.

One seasonal note. Greases stiffen in the cold, and a rubber bottom seal will freeze to a damp concrete floor overnight. The operator senses the resistance and stops. That is a genuinely common January call and often needs nothing more than a service.

The door is heavy, crooked, or will not stay put

This is the spring and cable family, and it is the group to take seriously. A balanced door stays roughly where you leave it. If yours does not, the counterbalance has failed and the door is unsafe until it is fixed.

The safe version of the balance test, and only if the door is not already obviously heavy: with the door closed, pull the manual release and lift the door only as far as it comes up easily, hands flat on the panel rather than curled round the bottom edge. If it resists at all, or you are taking real weight, put it straight back down and stop. That is your answer, and you do not need to go further. If it comes up freely, let go at about a foot with your feet and hands clear of its path. Balanced means it stays put. If it drops, the spring has lost tension or broken. If it climbs on its own, it is over-tensioned. In either case, put the door back down, leave it closed, and do not use it.

Signs to look for, by eye only:

• A gap of two or three inches in the torsion spring on the bar above the door, in what should be a continuous coil.
• On a canopy up-and-over door, the two halves of an extension spring hanging either side of the bracket.
• One side of the door sitting higher than the other. A lift cable has snapped or come off its drum. Sectional doors in particular jam hard in the tracks in this state, and can drop.
• A cable that is frayed, or noticeably slack on one side while the other is tight.

A door that has lost a spring or a cable is putting its whole weight through components never designed to carry it, and an electric operator will damage itself trying. Switch the operator off at the socket or fused spur so it cannot try to cycle, and do not pull the manual release, because on a door with a broken spring the operator is the only thing holding it up. Leave the door closed and read our snapped spring guide for what happens next.

If you are wondering why now: a standard spring is rated for around 10,000 cycles, with heavy-duty versions running to 25,000. At a couple of open-and-close cycles a day that is a long time on paper, but in practice most springs we replace have done 10 to 15 years, because a damp garage corrodes a spring long before it runs out of cycles. If yours has gone after a decade of ordinary use, nothing has gone wrong. It has simply worn out on schedule.

The motor runs but the door does not move

Watch the boom, the rail running back from the motor into the garage, while someone presses the button. What the boom does tells you which half of the system has failed.

The chain or belt moves but the door does not. The trolley that connects the door to the drive is disengaged, and far more often than not the manual release has been pulled. Re-engaging varies by brand: on most operators you pull the cord back toward the door, or run the operator until the carriage clicks into the trolley. Check the manual. If it will not re-engage, the trolley or its release catch has broken.

The motor whines but nothing on the boom moves. The drive has failed inside the head. On chain-drive operators the plastic drive gear in the gearbox is a known wear item, and a sheared chain or a snapped belt looks identical from the ground. That is an engineer job, and it is normally worth doing, because the rest of the operator is usually fine.

On a roller door, the tube motor sits inside the barrel. If it spins without turning the curtain, the crown or drive adapter has slipped, or the curtain has come loose from the barrel. If instead it moves but stops in the wrong place, the motor's internal limits have lost their setting. The other common version is a curtain that has come out of its guide at one side and jammed the barrel. Stop pressing the button at that point, because each attempt bends more slats.

The motor hums but does not turn. On a mains-voltage motor, which means roller-door tube motors and older AC operators, that is usually a failed start capacitor or a seized motor. Most modern sectional operators run a low-voltage DC motor with no capacitor at all, where a hum without movement points at a jammed drive or a failing motor. Either way, stop trying it. Repeated attempts overheat the winding and turn a cheap part swap into a new operator.

The door starts to close, then reverses straight back

This is the safety system doing its job, so treat it as information rather than a fault to override. Something is telling the operator the way is not clear.

Photocells. The most common cause by a distance. Check both lenses are clean, both indicator lights are on, and nothing crosses the beam, including low winter sun shining straight into a lens. Sensors get knocked out of alignment by a wheelie bin more often than by anything else, and a loose or corroded wire at one sensor gives you an intermittent version of the same fault.

Resistance in the travel. If the door meets friction, the operator reads it as an obstruction and reverses. Note the height at which it reverses, because that is where the resistance is. A collapsed roller, a bent track, a dry hinge or a frozen bottom seal are the usual causes.

The close limit set too low. The operator thinks the floor is lower than it is, so the door meets the concrete, senses resistance and backs off. The tell is that it reverses at the very bottom every time with no obstruction anywhere.

What not to do is wind the force setting up until the symptom disappears. Powered doors sold in the UK have to limit the force they can put into a person, and on a domestic operator that is normally delivered by the door backing off when it meets resistance. The standard behind it is BS EN 12453, and it is what a good installer force-tests at handover. Winding the force up raises how hard the door will push before it gives way, which is the one setting you do not want to be guessing at, and on an older operator that protection may be weak or absent to begin with. If your door needs more force than it used to, the right move is to find out why.

The remote does nothing but the wall button works

Good news first. The wall button working proves the motor, the door and the mains supply are all fine, so the fault is in the radio link and it is usually cheap. Work through it in this order.

• Batteries in both handsets. Handsets bought together fail together, which is why this so often looks like a motor fault.
• Lock or holiday mode on the wall console. On many systems this disables the handsets while leaving the button live, which is exactly the symptom you are looking at.
• Range. Does the handset work standing directly under the operator? If yes but not from the drive, you have a range problem. If it does nothing even at a metre, the handset or the pairing has failed.
• The aerial. Most operators have a thin aerial wire hanging from the back of the head. If it has been tucked up, taped along the metal boom, or snipped during a garage tidy, range collapses.
• Interference. LED lighting is the usual culprit. Cheap LED lamps and their drivers put out noise across the frequencies garage remotes use, and one new bulb in the garage or on the drive can kill your range overnight. Turn the garage light off and try again. If the range comes back, that is your answer.
• Pairing. Handsets can lose their code after a power surge or an operator reset. Re-pairing is done with a learn button on the operator head, and the sequence differs by brand.

Is this a repair or a replacement?

Nearly everything on this page is a repair, and usually an inexpensive one. The rule we use on site: if the door itself is sound, secure and reasonably straight, a repair in the £120 to £300 range beats a £2,000 replacement almost every time. The exception is a door needing repeated repairs, where the quotes start approaching a third of a new fitted door. We will tell you which side of that line you are on even when it means a smaller job for us.

A repair makes sense when the door is under 15 years old, the fault is mechanical (spring, cable, roller, motor), the panels are intact with no rust through, and parts for the model are still manufactured.

Replacement is the better call when several faults arrive at once (worn springs, tired cables, dry rollers and a failing motor together is a door telling you something), the panels are rusted through, dented through or warped, the door is over 20 years old with obsolete parts, or the door is mechanically fine but you want insulation, automation or better security. In that last case the fault is really an opportunity, and our 2026 garage door price guide sets out what a replacement actually costs. If you want to see the numbers move as you choose, you can design your garage door and build an itemised guide price as you go.

There is a useful middle option people often miss: a sound door with a dead operator. Automating or re-automating a good door is a much smaller job than replacing the whole thing, and we price it at survey.

What these repairs typically cost

Most garage door repairs land between £80 and £350 including the call-out. These are our typical 2026 figures, and you get a firm price on the spot once the fault is diagnosed.

That last row is worth dwelling on. Most of the emergency call-outs we attend had a warning sign that had been there for months: a new noise, a door that had got stiffer, a bounce at the bottom of the travel. Full detail on what we check and what we charge is on our garage door repair and maintenance page.

If you need someone out

We diagnose a lot of faults over the phone, and it goes much faster if you have four things ready: what the door does when you press the button, any noise it makes, the door type (roller, sectional, up-and-over or side-hinged), and the brand on the operator if it is automated. A photo of the spring above the door helps too.

We repair most makes and models across Reading, Oxford and the Thames Valley, including doors we did not fit, most repairs are scheduled within the week, and every repair carries a 5 year parts and labour guarantee. Call 0118 336 0212 or send us the details.

Safety note: the Health and Safety Executive's guidance on powered doors and gates sets out what obstruction protection has to do, not just stop when it meets something but back off far enough to release it. Health and safety law does not cover a homeowner's own garage door, but the engineering is identical, and a door that has lost that protection is a door to leave to an engineer. See the HSE guidance on powered doors and gates.

Frequently asked questions

Why will my garage door not open?

The most common causes are a flat remote battery, no power to the operator, a manual release cord that has been pulled, an obstruction across the photocell sensors, a door left locked, or a broken spring. Work through those in that order, because the first five are free to check and the last one is the only dangerous item on the list.

Why does my garage door open partway and then stop?

If it stops at the same point every time, something physical is in the way: a bent track, a worn roller, a dented panel or debris in the track. If it stops at a different point each time, it is normally the operator's force setting or travel limits. If it lifts a few inches then comes straight back down, suspect a broken spring.

My garage door motor runs but the door does not move. What is wrong?

Almost always the door has been disconnected from the operator by the manual release cord, so the drive runs while the door stays put. Re-engage it by pulling the cord back toward the door or running the operator until the carriage clicks into the trolley. If the motor whines and nothing on the boom moves, the drive gear, chain or belt inside the head has failed and needs an engineer.

Why does my garage door reverse as soon as it starts to close?

The operator has detected an obstruction. Check the photocell sensors first: clean both lenses, make sure both indicator lights are on, and clear anything crossing the beam. If the sensors are fine, the door is meeting resistance at the height where it reverses, usually a collapsed roller, a bent track or a bottom seal stuck to the floor. Never turn the force setting up to stop the reversing, because that removes the safety protection.

Can I open my garage door manually during a power cut?

Yes. Pull the manual release cord to disconnect the door from the operator, then lift by hand. Do it with the door closed where possible. If the door feels very heavy or will not lift easily, stop, because that points to a broken spring rather than a power problem. If your garage has no other entrance, have an external emergency release fitted so you are never locked out.

Why does my garage door remote not work when the wall button does?

The wall button working proves the motor and power are fine, so the fault is in the radio link. Check the handset batteries, then whether the wall console is in lock or holiday mode, then the thin aerial wire hanging from the operator head. LED lighting is a frequent cause of lost remote range, so try the door with the garage light off. If none of that helps, the handset needs re-pairing to the operator.

Why has my garage door suddenly become so heavy?

A spring has broken or lost its tension. The spring is what counterbalances the door's weight, which is typically 40 to 80kg on a single steel door, so without it you are lifting the whole thing. Stop using the door, switch the electric operator off at the socket so it cannot try to cycle, and call a garage door engineer. Do not pull the manual release on a door with a broken spring.

Is it safe to use a garage door with a broken spring?

No. Without the counterbalance, the full weight of the door bears on the mechanism, the tracks and on you if you lift it, and an electric operator can be damaged or stall trying. Springs and cables are also under extreme tension and should never be adjusted or replaced by a homeowner. Leave the door closed and get a qualified engineer out.

How much does it cost to fix a garage door that will not open?

Most garage door repairs cost between £80 and £350 including the call-out. As a guide, spring replacement runs £120 to £280, a spring and cable together £200 to £300, rollers and tracks £80 to £120 (up to £180 if a track is bent), and electric opener faults £100 to £250. You should always get a firm price after diagnosis and before any work starts.

How quickly can a garage door that will not open be repaired?

Most repairs are scheduled within the week across the Thames Valley, and a door stuck open is treated as a priority because it is a security problem as well as an inconvenience. We carry common springs, cables and spares, so a straightforward job can often be finished on the first visit.