The 456 rollover lane lamps won't change when I hit the left flipper button. The lights work, the switches work, the flippers work. The lit lamps just won't shuffle. The 123 lamps work fine. I don't see a second leaf switch at the flipper button. I have no idea where to look next. I know the left flipper somehow changes the lanes but I don't know how it does it.
I recently brought the game back from TPF. I suspected the connectors. I took them apart again and reseated them but no change. Any ideas?