GMCPauly,

A pretty perplexing problem. I am not sure this theory could involve all your gauges and indicator lamps, but I'll throw it out anyway.

If one of your taillights or park/turn lights was not able to find a ground in the light assembly, it is possible for it to back-feed through the system and power dash lights as it searches for a ground.

I would check my taillights and any park/turn lights when I had the headlight switch pulled on. Maybe you will see one that is dim...it could be the culprit.

I think this is the way it works!

Stuart