Liftmaster LA400 inconsistent gate operator problems Posted on September 17, 2016September 28, 2019 by wwilder Liftmaster LA400 inconsistent gate operator problems If you have a Liftmaster LA400 dual arm gate operator system and are unable to diagnose a problem using the manual or by calling technical support, be sure to check the wiring in the connection box. These boxes are not water proof so if not protected – during wet conditions the wires may not make satisfactory contact. Incorrect or insufficient wiring contact can produce problems that are not part of the standard troubleshooting process. Often times we find them buried in the flower beds – full of water!