I have two electrical switches that do not operate anything I can identify. I have always suspected that they are "prep" wiring for ceiling lighting, perhaps for fireplace spots. Tonight I began to remove panelling in the room getting ready to drywall. I can now see the wiring going into the ceiling at the top of the wall. Being a two story house I can't see where they go in the ceiling without tearing into the ceiling. Is there a way to trace the line(s)?