oon my 99 buick century, my cluster panel lights don't light up and when I pull the headlight button out my radio lights dimm. My headlights and dimmer work good

The radio light will dim when turning on the headlights. The cluster not lighting up may just be some burnt out bulbs. Just have to pull the cluster and check them, that is if you cannot get in behind it from under the dash.

My cluster panel doesn't have any bulbs. And the radio light wasn't ever that dim that I could not read the time. It never dimmed before.

Most likely the headlamp switch is bad. Common issue on these cars. To access it, pull the cover off the driver's side end of the dashboard and remove the two screws holding it in. Unplug it, and most likely you will see the plastic around one of the pins is burnt/melted. It's the circuit for the dash dimmer. When the headlights are off, the odometer and radio will be bright. When the lights come on (either manually or automatically when it gets dark), the lights dim so as not to be a distraction while driving, and the dimmer knob can be used to adjust it to your preference. When the switch fails, they go dim and eventually the dash lamps will also go inop.