Yup 04 gen 1 and no switch for headlight on/off
I aint much help as i have no idea how it dose it, but it is side lights while ignition is on and the headlights come on once the engine is turning over. its why if the battery isnt great it wont crank over because as it starts turning it over ( about its heavyest draw on battery i would think) it turns on the headlight lol just to ask even more of the battery.
but sorry im no help as to where the gubbins that dose that is located sorry. i allways just assumed it took it from the gen rather than the bat circuit