We're seeing the usual "two countries separated by a common language" issue...
In the US, "fog lights" refer to extra forward-facing headlamp units, usually mounted very low and frequently with amber lenses.
On my T1N, those would be turned on with a switch on the dash with a "headlamp with louvered screen" symbol. (if i had one).
In Europe, Max's "fog lights" are (US term) "marker lights"... small amber "parking lights" (as bright as a taillamp) which are left on all night on the road-side of a parked vehicle.
In my US T1N, the headlamp switch has the on/off control for that (with a "P" symbol).. rotate the headlamp switch to the "P", then lift or lower the switch stalk to choose which side actually turns on.
Such side-lights are not a "requirement" in the US (at least for passenger vehicles).
--dick (such side-lights were required/standard equipment on English cars in the 1960's)