Garage Door Will Not Close: The Checklist, In Order

Start with the photo eyes. They are the two small sensors mounted near the floor on either side of the opening, and they cause more will not close calls than everything else on this page put together. A large share of these visits end with a wipe, a nudge and no part at all, which is why we would rather you check them before calling anybody.

The rest of this is an ordered run: cheapest and most likely first, most expensive and least likely last. Do not skip ahead, because the expensive causes look like the cheap ones from across the garage.

Why the sensors sit at the top of the list

One sensor sends an infrared beam across the opening, the other receives it. Break that beam and a closing door reverses, every time, by design. They go out for boring reasons: a bike handlebar knocks a bracket, dust films the lens, a spider builds across it. Most units show status with a small LED, and a blinking one usually means the pair cannot see each other.

Wipe both lenses with a dry cloth, sight the two units at each other, and watch the lights. That is the whole first move, and it is the fix in a large share of these calls.

The checklist, in order

Work down the list and stop at the first thing that changes the behavior. Most people stop early.

1. Look in the opening. A trash bin, a bag of mulch, a bike pedal or a hose reel leaning into the path is easy to miss from inside the house.
2. Check both sensor lights and compare them. Steady on both sides is normal on most units. One out or blinking says the beam is broken. Read the label on the housing, because manufacturers do not agree on what each color means.
3. Wipe both lenses with a dry cloth. Dust and cobwebs cut the beam long before the lens looks dirty.
4. Check the brackets. Loosen the wing nut, sight one sensor squarely at the other, retighten.
5. Consider the sun. Low winter sun through an open door washes out the receiving sensor, so the door refuses in the late afternoon and closes fine at night. Shade the receiver with your hand to confirm.
6. Follow the sensor wire. Look for a staple driven through the insulation, a nick from a lawn tool, or a wire pulled loose at a splice. A partial short does the same thing as a blocked beam.
7. Check the wall control. Nearly every wall button has a lock or vacation setting, it is one press away on some, and it disables remotes by design.
8. Watch where the reversal happens. If the door lands on the floor and then comes back up, the close limit is likely set past the floor, so the opener keeps pushing after the door has landed.
9. Check the bottom seal. A hardened seal on a cold morning, or one stuck to a damp slab, adds resistance in the last inch.
10. Look at how the door meets the floor. If it touches down on one end first with daylight at the other, the slab has moved or the door is out of square.
11. Watch the last foot of travel. A sticking roller or a dry hinge adds drag right where the opener is most sensitive to it.
12. Last, check the door itself. Disconnect the opener and lift by hand. If it is heavy, drops when you let go, or a cable has gone slack on the drum, the door is the problem.

The wall button trick, and what it actually tells you

On most openers, holding the wall button down continuously forces the door to close, ignoring the sensors, and it stops the instant you let go. That is a deliberate design feature so a door can be secured when a sensor has failed.

The useful part is what it proves. If the door will not close from a press but closes while you hold the button, the mechanical side is fine and the sensors or their wiring are the problem. If it still will not close while you hold it, the sensors are not the issue and you are looking at limits, force, or something adding resistance.

When the door lands and comes straight back up

This one has a specific explanation. Travel limits tell the opener where the floor is. Force settings tell it how much resistance is normal on the way there. If the close limit is set past the floor, the door lands, the opener keeps driving, resistance spikes, and the opener concludes it hit something. Nothing is wrong with the door. The opener has been told the floor is lower than it is.

The same symptom comes from real resistance in the last inch: a hardened bottom seal, a slab that has heaved so one corner meets the door early, or a roller binding at the bottom of the vertical track. The order that works is find the resistance, remove it, set the limit correctly, set the force to the lowest number that runs the door through a full cycle, then test the reverse against a solid object on the floor.

When it is the door and not the opener

At the bottom of the list is the small group where the opener is behaving correctly and the door is the problem. A weak or broken spring means the counterbalance is gone and the door is genuinely heavy, so the opener stalls at the point where it has to control that weight on the way down. A cable off its drum, or slack on one side, lets a corner sit low and drags the door out of square, which shows up as binding at the same spot every cycle.

These have a clear signature. The door is heavy to lift by hand with the opener disconnected. It sits crooked when closed. There is daylight along one end of the floor. A cable hangs loose or wraps unevenly on its drum. There is a visible gap in one of the springs. Any of those means stop working the list.

What running the list saves you

Most people find the answer in the first six items, in the garage, in under fifteen minutes, with no parts and nobody paid. That is the point. Cleaning sensors, aligning sensors, clearing a lock button, replacing a remote battery and lubricating a dry hinge are homeowner jobs, and there is no reason for a service call on any of them.

What is worth a call is the far end: limits and force set and tested, a cable back on its drum, a spring measured and replaced, a frame that has moved enough to put the door out of square. Those need tools, a second set of hands, and parts sized to your door. Knowing which end of the list you are on is most of the value of running it.