License plate light

Does each state have a different law on license plate lights? My bike came with a fender elim kit that goes on top of the hugger. When I first got it the light was a strobe light. But it went bad on me just recently and there doesn't seem to be a way for me to replace just the light. I just wanted to find out if it was necessary to have a light on the plate. That way I can hold off on replacing the whole thing and just save up for a damper. Any feedback is appreciated, thanks.