It's weird that the parking lights are on when the headlights are off, but when headlights are on, the parking lights are off. I've seen some 65-66 Mustangs with the parking light on when headlights are on. Does anyone's lights work when the headlights are on? I'm assuming I'd need a double filament bulb to make it work like that. Just a curious question. Thanks Guys/Gals.