If your garage door won't close, check the safety sensors first. A blocked, dirty, or misaligned photo eye is one of the most common simple reasons a garage door starts down, reverses, or refuses to close.
What to check first
- Boxes, tools, bikes, leaves, or spider webs blocking the sensor beam.
- Dirt or condensation on the sensor lenses.
- One sensor light off, flickering, or blinking.
- Sensors that were bumped out of alignment.
- Objects in the track or a door that looks crooked.
Clear the sensor path
The safety sensors sit near the floor on both sides of the garage door opening. Move anything between them, wipe the lenses with a soft cloth, and check for spider webs or leaves around the brackets.
Check the sensor lights
Most openers use indicator lights on the photo eyes. If one light is off, flickering, or not showing the normal status in the manual, the sensors may be blocked, misaligned, dirty, disconnected, or damaged.
Gently adjust the sensor brackets until the lights match the normal status for your opener. Don't bypass the sensors. They are a safety feature, not a nuisance feature.
Watch what the door does
If the door starts down and reverses, sensors are a strong suspect. If the opener lights flash and the door will not close, many openers are warning about a safety sensor issue. If the door is crooked, jerky, or heavy, the problem may be mechanical instead.
Check the tracks without adjusting springs
Look for obvious objects in the tracks, bent sections, loose hardware, or rollers that look out of place. Do not loosen major hardware, remove cables, or adjust springs. Garage door springs are under high tension.
When to call for service
- The door is crooked or one side hangs lower.
- A spring is broken.
- Cables are loose, frayed, or off the drum.
- The door falls, feels unusually heavy, or will not stay open.
- The opener strains, grinds, or keeps reversing after sensors are clean and aligned.
- Sensor wires are damaged or the indicator lights will not come back.
Good maintenance rhythm
- Monthly: test the auto reverse feature if your opener manual recommends it.
- Every few months: wipe safety sensor lenses and check that both brackets are secure.
- When items move around the garage: make sure nothing blocks the beam.
- Yearly: inspect rollers, tracks, cables, and door balance from a safe distance.