lose wire or a wire is broken (fibers in side have broke) and when it moves i guess it making it trip the contacts, my sister car would lock or open i cant rember the door when ever i plug in or unplug the lock switch, if rain has something to do with it maybe water is getting in your door and crossing contacts and then you can always try boroing up the switch by coving the back of the wire harnest with some caulking