Sounds to me like the only reason they work with the bright light switch is because that is a really bright bulb and the gauges near it get some of that light off of it, your dash lights are out all together, you either have a short somewhere or a bad connection. Take the gauge panel out and wiggle the main connector, if that don't work you will have to look deeper...perhaps the headlight switch may have a bad lug on it or the reostat is bad in your headlight switch, in fact I would probably just go to AutoZone, pick up a 20 dollar headlight switch and try that first since its easy to take out...