Google "mustang fog light mod". You can make them turn on completely independently and most ppl do this mod. Basically you cut the power wire under the console for the switch and splice it with the convertible harness power wire which every car has, even hard tops. This gives it a constant 12v switched supply.
2000 Mustang GT Steeda #0048
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.