Garage door will not close; opener lights flash 1 time, pause, then 4 times repeatedly (logic board LED code 1-4).

Safety first: Unplug the opener before adjusting hardware near the tracks. Keep hands clear of the door path.

Steps to fix:

• Observe sensor LEDs while moving the door: With power on, slowly move the door by hand (with opener disengaged) and watch the receiving sensor LED. If it flickers, alignment is marginal.
• Tighten brackets: Turn off power. Tighten the mounting screws or wing nuts on both sensor brackets so they cannot wobble when the door moves.
• Fine-tune alignment: Slightly rotate or tilt the sensors until the receiving LED is solid and does not flicker when you gently tap the track.
• Shield from sunlight: If direct sun hits the sensor at certain times of day, install a small sun shield (piece of plastic or metal) above or to the side of the sensor bracket so the lens is shaded but the beam path remains clear.
• Check for track movement: Tighten the track mounting brackets to the wall and ceiling so vibration does not shift the sensors.
• Test operation: Restore power and run several open/close cycles. The 1-4 code should no longer appear if alignment is stable.