Figure this one out

Turn headlights on. Everything fine. All of a sudden - all the gauges go to full scale - if you pull tun signal down - both turn signal indicators flash together (inside - outside they work OK) - if turn light switch to dash lights off (counter clockwise) - gauges go back to normal, but dash lights go out. Does not do this all the time - just once in a while. Headlights work as normal when this occures.