Garage Door Won't Close? Check These Things First

1. The safety sensors

Every opener sold in the US since 1993 has had to include entrapment protection, and on most homes that means two photo-eye sensors near the floor on each side of the door. If the invisible beam between them is broken, the door will not close, or it will stop and reverse.

• Look at the lights on both sensors. Usually one is always lit and the other lights up only when the beam is lined up. A blinking or dark light means trouble.
• Wipe both lenses with a soft cloth. Spider webs and dust are common culprits.
• Check that nothing is in the path: a recycling bin, a rake, leaves.
• Gently re-aim a sensor that has been bumped until both lights are steady.
• Low winter sun shining straight into a sensor can confuse it. If the door only misbehaves at certain times of day, that may be why.

2. The close limit setting

The opener has to know where the floor is. If the close limit is set too short, the door stops a few inches up. If it is set too long, the door hits the floor, thinks it hit an obstruction, and reverses. New floor coatings, a new bottom seal or ice build-up can all change where the door meets the floor. Your opener manual explains how to adjust the limit, or a technician can do it in a few minutes.

3. Something mechanical is binding

Disconnect the opener with the red release cord, with the door closed if possible, and move the door by hand. If it is hard to move, jerky, or one side lags, the problem is the door, not the opener:

• A bent track or a roller out of the track
• Worn or seized rollers and hinges
• A frayed or broken lift cable
• A broken spring, which makes the door very heavy

4. Remote, keypad and wall button

If the wall button closes the door but the remote does not, replace the remote battery and check whether the opener's lock or vacation mode is on. If nothing works, check the outlet the opener is plugged into, and the GFCI reset in the garage. Garage outlets often share a GFCI with outdoor outlets, so a trip somewhere else can shut down the opener.

5. Weather

In cold weather the bottom seal can freeze to the floor, or snowmelt can freeze in the tracks. The door may stop or reverse because the opener feels extra resistance. Clear ice from under the door and from the tracks, and do not just turn up the opener force to push through it. See winter garage door problems.

6. The opener is disconnected from the door

If the motor runs and the light comes on but the door does not move, the trolley on the rail may be disconnected from the door. This happens when someone has pulled the red release cord. On most openers, running the opener through a full cycle lets the trolley travel along the rail and click back into place. If the trolley moves but the door still does not, or the chain or belt is slack or off its sprocket, the opener needs service.

Symptoms and what they usually mean

Closing the door if it is stuck open

If the springs and cables look intact, pull the red emergency release and lower the door slowly by hand, keeping your fingers away from the section joints. Many doors have a manual slide lock on the inside you can use until the opener is fixed. If anything looks broken, leave the door where it is, lock the door from the garage into the house, and call.

Sensor wiring problems

If the sensors are clean and lined up but one light stays off or flickers, look at the thin wires running from the sensors up to the opener. They are often stapled to the wall and the ceiling, and a staple driven through the wire, a wire chewed by mice or a loose connection at the back of the opener can cut the signal. Damp or corroded terminals at the sensor itself are another cause, especially in garages that take on water.

Sensor wires carry low voltage, and the connections are simple, but if you are not sure what you are looking at, a technician can test the wiring and replace the sensors in one visit. Replacement sensors must match the opener brand.

When to stop troubleshooting

Stop and call a technician if you see a gap in a spring, a loose or frayed cable, a bent track, a roller out of its track, or a door that sits crooked. Also stop if the door is very heavy when you try to lift it by hand. Those are mechanical problems that involve high spring tension, and no opener setting will fix them. Turning up the force to make the door close in those cases can damage the door and disables an important safety feature.