1974 Jeep DJ-5C electrical problem

I have a 1974 Jeep DJ-5C. Everything works great on it except none of the lights work on it. The brake lights, the turn signals, the backup lights, none of that work. All fuses from what I can see are good. Been trying to follow the wires to see if I can see something that is up, but have had no luck. The head lights work, but only in low beam mode. And an aftermarket fog light system works, but that is it. And the Jeep runs fine and fires right up. Any links to a wiring diagram that you may know of or if there is something real simple that I am missing?

Thanks.

On a '74, I'd suspect the headlight switch. IIRC, it's a pull/on push/off switch with a twist control for brightness?

Yep. That's the one.

Well, there are several connections in and out of the headlight switch; I'd start there.