Dashboard lights with no bright

If you move the panel dimmer for the dash lights do the bulbs get brighter and dimmer as it's rotated? From your description I would say that the dimmer section of the light switch is failing. Inside it is a layer of carbon on a circuit board that is riveted into place in the switch. Likely one of the rivets is loose or corroded.
To replace it you need to remove the dash trim panel. To do that you need a couple of plastic trim tools and some luck. First set the parking brake or chock the tires. Next remove the small trim panel around the ignition switch, and the end panels over the fuse blocks from both ends of the dash. Next- if you have a column shift, turn the key and shift into low. Then tilt the steering down as far as possible. Now for the part requiring luck. Remove the screws from around the instruments and the ends of the panel, then starting at the right side gently pull on the panel to disengage the retainer clips. Slowly work to the left side. Use the pry tools to hold or pry as needed to get the retainers free. This is 20 year old plastic so be gentle. Now you can either disconnect the electrical connectors or just prop the panel up out of the way and remove the 2 screws that hold the headlight switch. Remove it and check the electrical connector for melted plastic or any damage. Replace the switch and connector as needed and test that the dash lights now work. If they do then reverse the process to put everything back together.