Are you sure you checked the right fuse? I suggest you check them all because a fuse is the obvious (and cheapest) part that would cause both to go out. Next look at the relay. I don't know if the ST has a separate control circuit (i.e. fused power that powers only the relay (or the lighting relay and other relays)) separate from the headlight fuse. In this case, you would need to check both the headlight fuse and the relay's power fuse. As I said, check them all. I've had mud on my face because I looked at a fuse listing upside down and kept testing the wrong fuse.