ok call me silly, but i didnt see you post this or anyone else, did you check/change the bulbs/lamps?
and also if you have any slack on power and ground wires from the battery, you should check to see if they corroded from the inside. I had this happen once where they looked fine but when i cut a piece off it was all junk on the inside. also follow them to alternator and anywhere they go and check those connections for tightness/corrosion.