dash lights issue

Do you have a feel that anyone kinda hacked up the wiring? I can think of no crossover point that would connect the start or run circuit with the instrument lamps.

In case you are unaware, here is how they work. The headlights switch has two power sources. One, only for the headlamps, comes from the big welded splice in the ammeter black wire behind the cluster.

The park/ tail/ dash lamp power comes from a fuse in the panel. When the light switch is in park or head, power goes from the switch, through the dimmer control, and out of the tan wire, down to the fuse panel INST fuse. That then goes out on orange wires to all of the dimmer controlled dash lighting.

I am stumped