I have a 199 0cadillac eldrido dash lights don-t work

yes ,
check the fuses.

is battery good, check fuseable links under the hood and the light switch itself..

These are all different circuits. The brake lights are on a 10amp fuse - the headlights are on a 50amp fuse - and the parking and dash lights are on a 20amp fuse.
Do you have power going into the headlight switch and the brake light switch ?

sometimes when one of your bulbs is out it does that to all off the start with your turn signal bulbs other wise its you regulater fuse located under the hood

The tail lights are usually on the same fuse as your dash lights. Check to see if you have tail lights. If they are on and it's only your dash lights that don't work, check the dash dimmer switch for a fault.

I suggest you check the dash light dimmer control by the headlight switch it may be turned off or defective.

I have a 2003 Buick lesabre limited my inside lights don't work

You have a faulty instrument cluster.Replace instrument cluster

dash light fuse and back feed through a bulb

i had to disconnect the battery and reconnect on my daughters car and that solved her problem, worth a try!