Photo-eye sensor
A pair of infrared safety sensors mounted near the floor on both sides of the garage door opening that reverse a closing door if the beam is broken.
- Photo-eye sensor, one each side
- Infrared beam between them
- Anything breaking the beam reverses the door
- About six inches above the floor
The two sensors sit about six inches off the floor facing each other across the opening. One transmits an infrared beam, the other receives it. If anything interrupts the beam while the door is closing, the opener reverses.
Federal law has required entrapment protection on residential garage door openers sold in the United States since 1993, which is why an opener made before then should be replaced rather than repaired.
Misaligned or dirty photo-eyes are one of the most common reasons a door closes a few inches and then reverses, often with the opener light flashing. Cleaning both lenses and nudging one until its indicator light is steady is safe homeowner maintenance.
Two checks are worth doing yourself before booking anyone. First, look at the small indicator light on each sensor: both should be lit and steady, not flickering or off. Second, wipe both lenses with a dry cloth, since a spider web or a film of dust is enough to break the beam. If a light is off or flickering the bracket has usually been knocked, and gently twisting the housing until the light steadies fixes it. If neither light comes on at all, the wiring or the opener board is the problem and that is not homeowner work.
Most openers report sensor faults through their own light. A steady blink pattern on the motor unit — count the flashes — maps to a diagnostic code in the manual, and a beam obstruction is almost always among the first few. Two less obvious causes are worth ruling out before you call anyone: low afternoon sun striking the receiver directly can wash out the beam and produce a fault that only happens at one time of day, and a loose staple pinching the sensor wire behind the bracket will do the same intermittently. Both look like a failing sensor and neither needs a new part. If the fault is genuinely intermittent, note the time of day it happens before you call — that single detail often identifies the cause without a diagnostic visit.