Lew

i'm rewiring a les paul for a friend of mine, going from active pickups back to single conductor passives, i've got it to where i get sound from all 3 switch positions, but if it's on the neck or middle setting i get a hum that starts as soon as i touch anything metal on the guitar, can anyone help me track down my problem, seems like it's gotta be something simple i'm just overlooking, but i've looked it over and can't see anything wrong with it