If'n it was me, i'd just go to any parts store and they have the racks full of push pins, and all that funky interior stuff, Autozone has em anyway...grab another clip that fits the screw...you can unplug that box right there when you lift it up and see whats up...
i just had mine off a couple months ago and cant remember the set-up...If it screwed into a hole to size in the door or if it had a clip??