The LiftMaster LM56A Proximity Reed Switch is an OEM magnetic position sensor used on select LiftMaster commercial and residential operators to detect gate or door position without physical contact. Actuated by a nearby magnet on the moving assembly, this reed switch provides reliable open/close or travel-limit feedback to the operator’s control board, helping ensure accurate stopping points and proper safety logic. It is a direct replacement part for compatible LiftMaster gate operators and overhead door operators that specifically list LM56A in their parts documentation, making it a practical repair or upgrade for restoring consistent position sensing.
Installation typically involves mounting the switch at the specified location and aligning it with the magnet target, then connecting the two leads to the designated low-voltage input terminals according to the operator’s wiring diagram. Always disconnect power before servicing and verify correct operation through the unit’s diagnostics or a controlled travel test after installation. For compatibility, reference the operator’s parts list or service manual to confirm the LM56A Proximity Reed Switch is the required sensor for your model.
