Entire dashboard will go dark, then all warning lights come on?

At random intervals (20 times in an hour, once in a month, and everywhere in between), the entire dashboard will go dark, then all warning lights come on, then it goes back to normal.

Happens while driving at highway speeds, as well as while idling.

When it happens, climate control fans go off, but radio is unaffected. Headlights unaffected if in on position, but automatic setting doesn't work 50% of the time afterwards (until next day).