Headlight switch broke.  To turn the fog lights on, you pull the headlight
knob out.  What's happening in the switch is a little copper disc on the end
of the shaft is pulled onto a land on the back of the circuit board,
completing the connection.  This copper disc is held on to the end of the
shaft by (for lack of a better term) a nylon 'rivet' (actually, the shaft is
necked down to a pin, ran through the copper disc, then sort of melted to
retain the disc).  That disc has come off the shaft, and therefore you have
no more fog lights.

You can try carefully disassembling the switch, and fixing the fog light
portion...  probably just easier to get a new switch.