Photo-eye safety sensors have been mandatory on garage door openers for decades — they stop the door if the infrared beam is broken. In Stittsville winters, that beam fails more often from frost, salt film, and bumped brackets than from dead electronics. Understanding how they work saves you a service call when a cloth and two minutes of alignment fixes the problem.
How to tell if sensors are the problem
- Opener flashes lights and reverses when closing but may open fine
- One sensor LED blinking or off while the other is solid
- Door worked yesterday, failed after plowing or washing the driveway
- Garage faces the street — more salt spray on lenses (common on Hazeldean-facing bays)
Safe DIY steps
- Unplug the opener or use wall control — keep clear of the door path
- Wipe both lenses with a dry microfiber cloth (not abrasive pad)
- Check brackets are tight and sensors point at each other — same height
- Remove obstructions: shovel, recycling bin, bike tire in the beam
- Plug in and test — LEDs should be solid on both units
When sensors need professional repair
Cracked housings, chewed wires, or sensors that still blink after alignment may need new units or wiring — typically $150–$200 for sensor repair in our pricing table. If the door still will not close after sensors are clean, test balance and ice at the seal — see garage door won’t close in cold weather.