Garage Door Light Flashing But Won't Close When you see you garage door opener lights flashing and the garage door will not close, it could be the LOCK button or the safety reversing sensors. (adsbygoogle = window.adsbygoogle || []).push({}); . On some systems, the garage door opener installed on the wall will override commands from the remote control opener, and the system must be unlocked from the wall pad. Liftmaster malfunctions with unknown reasons. Symptoms and model number are given in the attachments. I could be wrong about it not being the lock button, but iirc if the lock is engaged, there will simply be no response from the opener except a flashing light on the wall station.