Garage door sensors are small but essential components that keep your family and property safe every time the door opens or closes. These photo-eye sensors sit near the bottom of the door track, on either side, and communicate with each other to detect obstructions. When they're misaligned, dirty, or damaged, the door may refuse to close, reverse unexpectedly, or behave erratically. ... https://absolutegaragedoor.net/garage-door-sensor-replacement/