The LiftMaster 41B873 (current number 041B0873) is a sun shield kit for the safety reversing sensors (photo eyes). When low morning or evening sun shines straight into the receiving sensor, it can blind it, and the opener won't close or reverses for no reason. The shields shade the lens so the sensors can see the beam.
Is sunlight the problem?
- Yes, if the door only refuses to close at a certain time of day when the sun lines up with the sensor.
- If it fails all the time, check the sensor alignment, wiring and lenses first; a shield won't fix those. Worn-out sensors: 041-0136 sensor kit.
Safety
Never cover, tape or bypass the sensors. After fitting the shields, place an object in the doorway and make sure the door reverses.
More: safety sensors.
Door won't close? Before replacing sensors, try our garage door sensor troubleshooting guide, or look up the blinking light code on your opener.
Sensor help
Door won't close or sensor lights blinking? Most sensor problems are alignment, dirt or a wire: how to fix garage door sensors (light colors by brand, alignment, 2-minute wiring test).