The Stovebolt Site Forums The Shop Area The Electrical Bay Electrical weirdness.. Turn signal, highbeam, gas gauge

I started the truck up the other day.. Had a half tank of gas. Flipped on the headlights and the turn signal indication lights, highbeam indication lights all came on and the gas gauge went down to empty.... The highbeams and turnsignals all still worked, but the indication lights were visibly on. I turned the headlights off and everything went back to normal and the gas gauge went back to a half a tank. What do you guys think the deal is?? Ever heard of this? I haven't changed any wiring.. BTW, it's a 72 Chevy C10.. Thanks!!!!