No dash lights, CAB lights, taillights, or front marker lights?

Hi,

Interesting. This is a straightforward circuit. Power from fuse 4 in the fuse box goes direct to the headlamp switch via a tan wire with a white tracer. From there, power from the switch goes to the brown wire you mentioned.

I attached the wiring schematic below. When you checked fuse 4, did you confirm there is power to and from it? If not, do that.

Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Let me know.

Take care,

Joe

See pic below.