in the darth vader castle level where that guy(ive been stuck to long to rmember the name) is holding up the electric thing with his arm force powers(ooooo) and hes asks you to go find a swith to drain the water but i cant find it i looked everywhere and i found a switch but it doesnt do anything(its in a control room thing)

You have to use force push or pull on generators located on the side of the room. There is three of them. Ill try to get pictures for you.