Garage door won’t close

1 · Safety sensors are blocked or misaligned

Residential openers manufactured on or after 1 January 1993 are required to include entrapment protection under the UL 325 standard, referenced by the US Consumer Product Safety Commission. In practice that is almost always a pair of photo-eye sensors near the floor on each side of the opening — UL 325 calls for the beam to sit no more than six inches above the floor. If the beam breaks, the door will not close. That is the safety system working, not a fault.

Check for a bin, a bike wheel, a coiled hose or a stack of leaves sitting in the beam. Then check the small LEDs on each sensor — on most brands one is steady and one flickers when alignment is lost. A sensor knocked out of line by a snow shovel or a car door is extremely common.

When it needs a technician: the beam is clear, both LEDs look right, and the door still reverses. That points to a damaged sensor, a pinched wire in the track bracket, or a failing opener logic board.

2 · The close-limit or force setting has drifted

Openers have adjustable travel limits that tell the motor where the floor is, and a force setting that decides how much resistance means “something is in the way.” These settings can need readjustment over the life of the opener, and a door that has become harder to move — through wear, poor lubrication or a spring losing tension — can start tripping the force setting even though nothing has changed in the opener itself.

A door that reaches the floor and immediately rises is almost always reading normal contact as an obstruction.

When it needs a technician: adjusting limits on a door that is also out of balance masks a spring problem and puts the opener under load it is not designed to carry. If the door is heavy to lift by hand, the limits are not the real fault.

3 · A cable has slipped or snapped

Lift cables run from the bottom bracket up to a drum at each end of the torsion shaft. If one slips off its drum or frays through, that side drops and the door binds in the track. It often still opens, which is why people assume the problem is the opener.

This is not a DIY repair, and the door should not be operated. Lift cables are under load from the springs. If the door sits visibly crooked, or you can see slack or frayed cable, stop using the opener, do not try to move the door by hand, keep people and vehicles clear of the opening, and call for service.

4 · The door is off track

Rollers can jump the track after an impact, or when a track bracket works loose. Once a door is off track, forcing it with the opener bends the track further and can damage the panels.

Stop using the opener and leave the door where it is. A door that has left its track is not stable. Do not force it, do not try to reseat it, and keep people and vehicles out from under the opening. Continuing to run the opener turns a bracket-and-roller job into panel damage — and an unsupported door can move without warning.