Fuel gauge power source?

[CURSED GEARS]

Hello. Just finishing a 7 year rebuild on my 1970 C10. I got it running and I'm trying to button up the gremlins. While test driving it, a new fusible link blew, stranding me on the highway. Prior to the link blowing, I noticed the fuel gauge had stopped working. My mechanic told me I used to small of a wire for the fusible link, and that is why it blew.
Once we hooked up the correct size wire, I drove home and went to see why the fuel gauge wasn't working. On the fuse block where the wire to the tank connects, has no power, where it did before. I checked the pink wire that plugs into the dash panel, and it has power.
I guess my question is two fold. On the back of the fuse panel where the gas tank wire goes, is a brown wire. No power on the backside either. The questions are, where does the brown wire and the pink wire meet? Where is the end of the brown wire go? The end of course, is in the fuse block. Why does the fuse block no longer have power at the fuel connecter?
I completely went through the wiring harness while the truck was apart, fixing wires that was questionable, or hacked from previous owners. I also switched from idiot lights to gauges. I got 99 percent of my information from this site. Repinned everything. It all works with the exception of the alternator, as I'm waiting to purchase o shunt from Stewart Warner next month when they start selling them again.
Any help would be appreciated.