Replace any fuses and/or relays for the lights in either fuse box. Something may be getting hot and causing an open condition.
Panama City, Fl.
I wake up in the morning with nothing to do and by supper time, I have half of it done.
2000 Lightning, s/c, tuned, Basanni, built tranny
Sold them all.....
Previous Mustangs:4 - '66 Coupes(silver/blue/grey/red) '87 GT HO, '00/'02/'07 GT Vert(red)(grey)(black), '68 Coupe, '11 GT/CS, 08 GT Vert