hope this helps , and is not boring.take a 12 volt+ from cigerette lighter supply. to your choosen switch. then a wire from your switch ,feed a coil of a relay (12volt) +. the 12volt - for the other side of coil take to body work (metal) .this will allow the relay to go on and off from your choosen switch . a12volt +supply from your battery to a inline fuse of a rating of 5 amp should be sufficent.from the other side of fuse holder take awire to your neons,this willbe 12volt+. from your car body work,take a wire to the negative side of your neon. please note this is only one option of many. there may be a simpler way that other people have knowedge of .