this problem happened, then cured itself, and a few months later came back. When you flip to dims, the headlights go out and if the fog lights are on, they also do not light up. All other lights are normal. Flip back to brights, and the headlights come on bright, and the fog lights are not on (normal), but again, flip to dims with the fog lights on OR off, and the dim lights do not light up and the fog lights do not light up. There appears to be a relay or something in the schematic that coordinates the headlights with the fog lights, and wonder if that could be bad, and where that is located.