In this video

Locate the garage door safety sensors mounted near the bottom of the garage door tracks, typically one on each side. These sensors project an invisible beam across the garage door opening. Check if the indicator light on each sensor is illuminated. If a light is off, it could indicate a power issue or a severe misalignment. Test the sensors by interrupting the beam (e.g., by placing a hand between them); the light on one of the sensors (often the receiver) should turn off and then back on when the obstruction is removed. The video highlights that a *flickering* light on the primary sensor (emitter) is a subtle but critical indicator of misalignment that can be easily overlooked.