individually

I put my car in the garage every night. When I take it out in the morning the headlights come on but quite often only one front foglight comes on and I am struggling to work out why. I know they both work because when I turn them on as fog lights for real, they both work. Is there some...

Yes, I'm in relaxing festive mode - my mind wondering into absolute trivia. I wondered how much it would cost if you bought all the parts to a car 'off the shelf' at full retail price v cost of a car from the factory?