The LiftMaster 41A4373A Safety Sensor Kit is a photoelectric safety reversing system for compatible LiftMaster, Chamberlain, and Sears Craftsman residential garage door openers that were originally equipped with this style of sensor in the early-to-mid 1990s. The pair of photo eyes (sending and receiving units) projects an invisible infrared beam across the door opening; if the beam is blocked during closing, the opener stops and reverses to help prevent entrapment, in accordance with UL 325 requirements for garage door operators. Designed for legacy systems, this kit serves as a direct replacement for worn or failed sensors on openers that specifically called for part 41A4373A.
These low-voltage sensors are powered by the opener head and typically mount to the track or jamb near the floor on each side of the doorway. Proper alignment is required; the built-in indicator LEDs will signal when the beam is aligned, and misalignment will prevent the door from closing using the remote. Wiring connects to the opener’s dedicated sensor terminals (commonly the 2 and 3 terminals on many LiftMaster units). This kit is suited for residential repair and maintenance where the original system used 41A4373A sensors; newer openers may use a different sensor kit (often sold under replacement part numbers like 041A5034), so confirm compatibility by checking the opener’s model number and original parts list. No external power supply is needed, and no programming is required beyond mechanical alignment once installed.
