Dash light won´t work, need help!

Has the car been re-wired?

The dash lights are "a bit of a trick"

Dash light power originates "in the switch" in the parking / tail light circuit. That is that tail fuse must be good and supplying power to the switch.

From the switch power goes to the dimmer control at the front of the switch. THAT POWER then goes (tan wire) down TO the fuse panel to the "inst" (instrument) fuse at one end of the fuse panel. From there the lamps power is distributed to dimmer controlled lamps via orange wires.

So...first thing I'd do is get a test lamp or meter and see if you have power on both ends of the inst. fuse. Make sure you "wiggle" the knob left / right and end up "left" (counter clockwise) which is "brighter" on the dimmer control.

Do ANY dimmer controlled lamps work, IE radio, heater bezel, shift quadrant light?

"Might be" a ground problem in your cluster or otherwise either bad connection at the harness connector or pins on the PC board.