Yes, that's a self-resetting circuit breaker that uses a bimetal strip like a turn signal flasher. It allows the headlights to flash in case of an overload, instead of going out and staying off. It protects the wiring without totally losing the lights. Good idea, and it's better than having a fuse or a manual-reset circuit breaker that would disconnect once and stay off. In case of a dead short between the battery and the headlight switch, most modern cars have a big fusible link that burns out if the current draw is excessive. When I do a rewire, I include appropriate-sized fuse links on all the major current draw circuits.
Jerry
