Problem
Garage door sensor light blinking
Two small boxes sit at the bottom of the door opening, one on each side. When they can't see each other, the door won't close. You can usually fix this yourself.
Your call goes to an independent garage door contractor.
Try these
Clear the path
Move bins, bikes and shovels, and any snow or ice against the track. A knock from any of them can shift a sensor.
Wipe both lenses
Use a soft dry cloth. Frost or a film of dust is enough to block the beam.
Line them up
Both should sit at the same height and point at each other. Bend the bracket gently by hand until the light on each stays steady.
Think about the sun
If this only happens at a certain hour, low sun may be shining straight into one sensor.
Try the door
Give the lights a moment to settle, then close the door.
Check the height
The U.S. Consumer Product Safety Commission says electric eyes should sit 4 to 6 inches above the floor. Mounted higher, they can miss a small child or a pet, so don't raise them to keep them out of the snow.
If that didn't fix it
A sensor with no light at all usually has a power or wiring fault. The thin wire along the wall can get nicked by a staple or a shelf bracket. That's a good point to call, and to tell the contractor which sensor is dark.
To get the door shut in the meantime, see the page on doors that won't close.
Need someone to look at the door?
Call this number to reach an independent contractor. Say what the door is doing, whether it is stuck open or shut, and what happened just before it stopped.