which fuse controls the license plate light on 2003 pontiac bonneville

Probably the same one that powers the tail lights. If you can't get an answer by internet inquiries, turn on the parking lights and then begin pulling fuses (if the light is on, pulling its fuse will shut it off) or pulling fuses and replacing them with a known good fuse until the light comes on or a fuse you pull is obviously blown and needs replacement. If neither of these helps you, or you find a fuse socket that blows the fuse immediately when a good one is installed, then there is a short in that circuit you will have to trace down.