2003 Chevy Malibu interior help needed

I have a 2003 Chevy Malibu, and for some reason, my dash display, as well as the lights for the thermostat aren't lighting up. The light dimmer switch isn't working as well. If someone can give me some insight on how to fix this problem, I would really appreciate it. I just think it's weird because all of the warning lights work, and the mileage gauge works in the daytime, but at night, when the lights are on, the mileage gauge gets dim, and I can't see anything on my dash display or on the air conditioning unit. Thank you..