I got my 03 Deville the other day. When you turn on the headlights they work fine. If you turn on the highbeams all of the headlights go out. I assume the lowbeam turns off when the highbeam comes on, but the highbeam bulbs don't look burned out. They do however look like a pain to get to to change. Does anyone know of a problem with the wiring or a short that could be causing the highbeams to not work at all?