Published 2026-05-05 · Houston Garage Door Pros
Garage Door Sensor Blinking? Photo-Eye Alignment Walkthrough
Quick answer: A blinking photo-eye sensor means it is misaligned or its view is blocked, so the door will not close. Clean both lenses, then loosen the wing nut on the blinking sensor and adjust its angle until the LED glows solid and steady. In Houston, slab settlement is the usual reason the alignment drifts out over time.
What the lights mean
Each photo-eye has an LED. One sensor sends an invisible beam, the other receives it. A solid steady light on both means they see each other and the door will close. A blinking or off light on the receiving side means the beam is broken: blocked, dirty, misaligned, or unpowered.
Before adjusting anything, wipe both lenses with a dry cloth. A spider web or dust film is the cause more often than people expect.
The alignment steps
Loosen the wing nut or screw holding the blinking sensor in its bracket. Sight along it toward the other sensor and tilt it slowly until the LED stops blinking and glows solid. Hold it there and retighten. If it will not hold steady, the bracket may be bent or the slab it mounts to has shifted.
Test by closing the door from the wall button. If it closes fully without reversing, you are done.
The Houston slab factor
Houston's expansive clay soil moves the slab through the year, and the sensors bolt to that slab. That is why a door that closed fine in fall starts reversing in spring. If realignment keeps drifting, we can remount the sensors to tolerate more movement, $95 to $170, waived against a repair.
Frequently asked
Why is only one sensor light blinking?
The blinking one is the receiver that has lost the beam. Adjust its angle until it sees the sender's beam again and the light goes solid.
Both lights are off. What now?
No power to the sensors. Check the opener is powered and the sensor wires are intact and connected at the opener head; a chewed or pinched wire is common.
I cleaned and aligned them and it still won't close. Why?
Either a wiring fault, a dead sensor, or a close-force setting issue. At that point a quick service call settles it; the diagnostic is waived on repair.
Can I just disconnect the sensors?
No. They are a required safety device. Realign or replace them rather than bypassing.
Why does this keep happening in my garage?
Houston slab movement repeatedly nudges the sensors out of line. Remounting for more tolerance reduces how often it recurs.
Related reading
- Garage Door Won't Close: Start Here
- Opener Repair Service
- Opener Not Working: 12-Point Diagnosis
- Houston Cost Guide