The whole wiring system on the headlights in foxes is completely terrible even when they were new. Many ppl do a full re-wire and put them on a new circuit. You could always do something like how the 94-98 DEPO aftermarket lights do and have an independent harness with relays that bugs directly into the battery and the only factory wiring that is used is the on/off signal wire.
2000 Mustang GT Steeda #0048 34k miles. 99 Cobra 4V swapped, FTBR IRS swapped, exhaust, tuned by James Gordon.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.