I've been slowly working on digging the Poster Child out from under the dirt and debris that has collected in it over the years and starting to breath life back into it. After showing the spiders that I would not let them intimidate me

I spent a few days cleaning up the dash and digging through my inventory to find suitable replacement parts. I replaced the glove box door, the center dash panel, the dash map light, the instrument cluster, the speedometer, the horn button and polished everything that would take a polish.
Then it was time to put a battery in. From the condition of the cable ends, it was apparent that the Patrol had still been running positive ground. I decided that this was a good opportunity to convert to negative ground. This required replacing the cable ends (they needed replacing anyway), reversing the wires on the back of the amp gauge and touching a jumper wire across 2 terminals on the voltage regulator. And keeping my fingers crossed.

Battery in, connectors on, no smoke, life is good.

Now to see what works. Turn the key and press the button; nothing.

Push the horn button; a faint clunking noise under the hood. Flip the dash light switch - nothing.

Headlight switch on; we have headlights!

And parking lights and tail lights! Yay. Time for a break - I can only keep the spiders at bay for so long.
My next attempt, with gritted determination - and teeth, the spiders ya know - required a printout of the wiring diagram. Take the dash back apart and mess with the dash map light. Did you know that the dash map light uses the same ground wire as the windshield wipers? True story. And guess what? The wires to the windshield wipers are cut inside the glove compartment. So, located the black wire, stripped the end, touched it to a good ground and viola, the dash light works. I'll work on reconnecting those wires later.
Now for the horn. I was pretty sure I knew where the problem was. Open the hood and chase away more spiders, find a stick to remove the webs with.

I dusted off the fuse box and removed the cover. Checked all of the fuses for power and everything was good there. Next I checked the horn relay for power; it was getting power. I used a jumper wire to jump power to the horn and it honked, so I knew it was good. Since the wiring harness looks fine the problem is most likely in the horn relay. After persuading the nuts to come off, I freed the horn relay from it's fender imprisonment and carefully carried it to the workbench. It's not like we can get these parts easily, so we have to try and repair them. I bent the little tabs out and removed the cover from the horn relay. It looked good inside, no corrosion, so I just used some carbide paper to clean the two contacts and used a wire brush on the terminals. Before I put it back together I ran a thin bead of clear silicone around the lip of the cover, just for a bit of added protection from moisture. I replaced the relay back in it's fender imprisonment and connected the wires to the terminals. Now when I pushed the horn button I was rewarded by the musical toot of two Patrol horns! Success!
Since I was in the neighborhood, I figured I might as well check the starter relay also. Checked for power; it's got it. Time to free it from it's fender imprisonment as well. At the workbench I carefully pried back the tabs and removed the cover. Horrors! It looked like it has been submerged in the ocean!
No amount of cleaning up was going to save this relay. It's a good thing the Poster Child is parked next to a '65 Patrol parts donor. I removed the starter relay from the donor and opened it up. Much better. All it needed was a little cleaning of the contacts and it was good to go. Put it in PC, hooked up the wires, turn the key, push the button and it responded by cranking the engine over!

Yippee!!!
Now to work on the tail lights, but that's another day.
Here are some before/after pics of the dash:
