VTecnician

...The main reason for this lock's failure (that I have repeatedly witnessed) is where the motor contact terminals plug in to the motors brushes. This is because the motor can move very slightly due to the torque still applied to its worm drive once the mechanism has reached its limits either direction. These terminals simply push in/pull out with slender pliers from the lock body. The poor conductivity occurs between the contact's inner pin and the armature brush contacts inside the motor. Often this can be restored simply by repeated extraction/insertion of the contact terminals (ensuring that you note their orientation, as the motor end of the terminal is offset). There is no requirement to disassemble the lock body unless any of my solutions here haven't restored connection to the motor. Whilst extracted, the terminals can also be cleaned with e.g. a glass fibre tipped contact cleaning pen. However, both these methods may only restore operation for a short while before again losing good contact. My suggestion is to remove both terminals from the lock, then 'tin' the motor ends of the terminals pins with solder making sure there isn't too much excess. This gives the motor's brush contacts better chance to retain good connectivity. Please "Like" this comment if either solution works for you.