--------" " "FIRST " " "--------- thing to do is to see if the "orange" dash lighting circuit is operating
THAT CIRCUIT is a bit of a trick
There are TWO sources of power to the light switch. One, from the ammeter circuit, supplies ONLY the head lights, nothing else
The second comes from the tail light circuit fuse, and supplies the tail, park, and dash light dimmer controlled lighting. That circuit goes to the dash light dimmer and through it, and OUT of the light switch on the TAN wire, which feeds TO the fuse panel TO the inst fuse, the fuse at one end of the panel---through that fuse and to all dimmer controlled dash lighting via ORANGE wiring.
So for that to work, the tail lights must be working, and turned on, the dash dimmer must be working, and turned "somewhat to the left" and the INST fuse must be good. Probe that fuse with the tail or head lights on, wiggle the dash dimmer and see if there is power on either fuse clip for that fuse