Flipped the fog light switch, heard a pop, smelled smoke. Got out of the car and called 911 while getting the fire extinguisher. Police and Fire Dept. arrived in under 4 minutes, but the car was a bit melty from the fire wall rearward. The engine was fine afterward, but the windows all turned black and broke, the dashboard, steering wheel and center console melted and the upholstery looked like the inside of a dirty barbecue pit.