2000 Lumina mystery dash lights

We have a 2000 Lumina that the dash lights mysteriously go out on after about 3-5 minutes of on time. It has DRL's and it does it when they are on or the normal driving lights are on. Can anyone help as to why this is doing this? Thanks!!

I'd pop the IP dimmer control out and wait for it to happen. Then see how hot the body of the switch gets. Warm is OK, hot is not. If you have a test lamp or meter you can avoid the previous step and just activate the lamps, wait for them to go out, and see if the gray wire coming out of the panel dimmer is at least battery voltage with dimmer at full brightness and gnd or com lead of meter to chassis ground. If at this time you have normal green turn lamps in the inst panel when you kick in the 4-ways, then you know the ground to the inst lamps is OK, as they share the ground with the turn bulbs and others.