I just got a 2000 Blazer and the first night when I went to adjust the brightness the dash lights, time/direction indicator, and radio lights went out.

During the day they work unless I turn the headlights on. As soon as you turn the headlights on they all go out.

Once it gets dark it doesn't matter where you have the headlight switch, they do not work.

I checked the fuses and they are not blown.