the lighting system is all integrated into some sort of computerized controller (controls timing of headlights after engine shutoff if u left the lights on, fogs, dome light/reading light auto shutoff etc). theres modules that override it in jdm land i believe, i havent looked too deep into it.

the fog light has its own switch, but its not like an on/off switch.

example: u turn the headlights on and press fog lamp switch once. - fog lamps illuminate. u turn headlights off, the fogs turn off with it. the next time u turn on the headlights, the fogs dont illuminate again, until u push the button to.