Garage Door Won't Close? Check the Sensors First
Short answerA common reason a garage door won't close is misaligned or blocked safety sensors. Check that nothing blocks the beam, clean the lenses and aim the sensors at each other. If that does not help, look for binding, an unbalanced door or wrong travel and force settings. Test the safety reversal after every change.
Safety first
- Do not touch springs, cables or the brackets they attach to. They are under extreme tension and can cause serious injury. Call a trained technician.
- Keep people and pets clear of the door, and never walk under a moving door.
- Do not raise the force setting to make a sticking door close. That can defeat the reversal safety. Do not disconnect or bypass the sensors.
Likely causes
| Cause | How to tell | What fixes it |
|---|---|---|
| Misaligned or blocked sensors | The door goes partway down and reverses, and the opener light may flash. | Clear the path, wipe the lenses and realign the sensors until their lights stay steady. |
| Obstruction or binding | The door stops or reverses at the same spot, or the track has debris or a bent section. | Remove the obstruction. Have a technician fix bent tracks or rollers. |
| Wrong travel or force settings | The door stops just short of the floor or reverses right at the floor. | Reset the limits following the opener manual, using the smallest force that closes the door. |
| Door out of balance | With the opener released, the door feels heavy or will not stay where you stop it. | Call a technician. Do not adjust the springs. |
What you need
- Soft cloth
- Screwdriver or wrench, for sensor brackets
- Short piece of 2x4 for the safety test
- Owner's manual for your opener
How to fix it
- Check the sensors. The small sensors sit low on each side of the door. Remove anything between them. Wipe the lenses with a soft cloth, including any cobwebs.
- Align them. Loosen the bracket gently and aim the sensors at each other until the lights stay steady, then tighten it. Check that they are mounted 4 to 6 inches above the floor.
- Look at the door path. Look for debris in the tracks and for bent or damaged sections. Do not force the door. Fix what you can reach safely, and call for the rest.
- Test the balance. First look at the springs from the floor without touching them. If one is broken, or you heard a loud bang, stop and call a technician. If not, with the door fully closed, pull the quick-release handle and move the door by hand. A balanced door stays in place when you stop it partway. If it is heavy, sticks or drops, stop and call a technician.
- Reset the travel and force limits. Reconnect the opener and follow the manual for your model, since the controls vary. Fix any sticking first, and never set more force than the door needs to close.
- Run the safety test. Lay a 2x4 flat on the floor in the door's path. The door must reverse when it hits the board. If it does not, disengage the opener until it is adjusted, repaired or replaced. Repeat this check every 30 days.
When to call a professional
- The door is heavy, uneven or crooked, or a cable looks loose or frayed.
- A spring is broken, or you heard a loud bang.
- Tracks or rollers are bent, or the door fails the safety test after adjustment.
What it costs to have fixed
Garage Door Repair is estimated at $80 to $620 nationally. See your state
Common questions
Why does my garage door go down and then back up?
A common cause is the opener seeing an obstruction, from misaligned or blocked sensors or from a sticking door. Align the sensors first, then check the track and the settings.
Why won't my garage door close all the way?
The travel limit may be off, or the door may be binding or unbalanced. Check the balance before you change settings, because limit and force settings only work right on a balanced door.
How do I test my garage door's safety reverse?
Lay a 2x4 flat on the floor in the door's path and close the door. It should reverse when it touches the board. CPSC says to inspect the door and opener every 30 days.
How do I get my garage door out of lock mode?
In lock mode the remotes stop working, and the wall control's indicator light flashes. A copy of a 1995 LiftMaster wall control manual (Model 68LM) on ManualsNet says to press and hold the Lock button for 2 seconds to turn it off. Buttons vary by model, so check your own manual. Source
Will unplugging a garage door opener reset it?
It can clear some faults. Chamberlain tells owners to reset the system by unplugging the unit for 30 seconds for one light fault. It is not a fix for every problem, so check your model's manual if the trouble comes back. Source
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Last verified 2026-11-01
Sources
- Chamberlain: My Garage Door Will Not Fully Close — Causes, order of fixes, not raising force to compensate for binding, and the reversal test with a 1-1/2 inch object
- CPSC: Non-Reversing Automatic Garage Door Openers Are a Hazard — Electric eye height of 4 to 6 inches, the 2x4 test, disengaging a non-reversing opener, balance, using the quick release, and inspecting every 30 days
- DASMA: Garage Door Openers Safety Tips — Photo eyes no higher than six inches, balance problems needing a trained technician, and watching the door until it closes
- DASMA: General Code Inspection Guidelines (TDS 151) — Components under spring tension are under extreme tension and should not be touched
- DASMA: Inspection Checklist for Sectional Garage Doors (TDS 167) — Not operating a door with a broken spring
General information, not professional advice. Conditions, codes and prices vary. Turn off power, gas or water before any work, and hire a licensed professional when in doubt. Cost figures are our estimates, not quotes.