Hi,
unlikely to be related as the headlight switch isn't fused in the normal wiring, but like the Horn it runs off the fuse block from the same side as the power coming in, meaning it doesn't pass through the fuse itself.
But that was from the factory and if someone has been playing and moved the horn, the purple wire Tim mentions and the headlight wire, heavy Brown or Blue wire to the other side of the terminal block and a fuse has blown then yes it could be related.
Terry