1970 Dart Headlight Switch

You need power out of the other end of that fuse. I've seen glass bar fuses broken underneath the metal end cap and crusty contact clips in the fuse box too. There are other lamps on this orange wire circuit. Checking power through the dimmer to orange wires is easier checked at those locations. Do radio, ash tray, shift indicator lamps work?
I don't argue that the dimmer is a common culprit turning off all these lamps. May as well fully diagnose.

I pulled the fuse and checked it with a multimeter and it is good. I cleaned off the contacts before I put it back in, and I am getting power on both ends of the fuse.

I have turned the switch back and forth many many times hoping that would clean the contacts and make it work.

There is an aftermarket radio installed by the previous owner, and my ashtray has no light socket anywhere to be found.

I don't have shift indicator lamps. Are these lamps located on the steering column itself??

Thanks!