Now, let's talk some "upgrades".
There's three parts of the wiring harness that are designed in a questionable way. The horn ground, and both of the brake light switch connectors that combine a green and white wire.
I find these "questionable" because they both attempt to combine multiple wires at the same time from a single connector. BOTH of the brake switch connectors either failed or had a wire snap off because of this design. And even then, this only "worked" originally because Columbia used super cheap wire with super thin insulators. I, on the other hand, did not use super cheap wire. I used automotive grade GXL wire, with hearty protective wire jackets. So combining wires into connectors like this isn't an option.
So the first "modification" I have on this wire harness remanufacture is to not do this awful design. Instead, any time two wires are being terminated into one connector, I instead will splice them together on the same side of an appropriately sized butt connector, and then run a short wire to the actual terminal at the end. All butt connectors will also have proper shrink wrap applied to them so that there's no stress on any of the wires that might result in the connection failing like they did on the brake switch wires.
Pictured below, the new horn bolt ground ring, and the two new switch connections (before being combined).
Now, on the subject of terminals. I will say that this entire project absolutely relies on using a proper ratchetting crimper- and ratchetting crimpers take a slight bit of getting used to before they can actually do any good. But once you get the hang of it, it's a breeze.
I also recommend getting an abundance of terminals (non-insulated). You will need them because sometimes terminals fail when you're putting them together. A ratchetting crimper will let you get the absolute best results from them, and you get the benefit of being able to get a huge bunch for super cheap. Like $10 for 50-100 from an electronics supplier.
To prove my point, here's a comparison of: Two failed test terminals because I used the wrong crimper die, a meh/failed terminal that didn't quite grab properly due to using one setting too high on the die, and a properly crimped terminal. This is all compared to one of the factory terminals, which is pretty damn bad.
Here's a better close up (and yes, I know, I needed a bit more wire stickout, I removed replaced this end after taking this comparison)
And finally, an issue of backwards compatibility. You ever noticed how all of the male spade terminals have a small hole in them? From the tiny ones on your brakes to the big ones from your headlights? Well, there's a reason for that- the female terminals are supposed to lock on to them- this is good, but also kind of bad.
A problem you may find when buying modern terminals is that they grip exceptionally well, and often have those locking tabs built into the female ends- even on cheap ones. Back in the days, you had to pay extra to get those, so vehicles were designed without them in mind. You may find that the 2.8mm spade terminals (yes, they are 2.8mm, not 1/8") are exceptionally difficult to remove from your brake switches if they have those locking tabs.
I found this out the hard way, took a solid few minutes of prodding with a toothpick before I could get a single one of those terminals off of the switch I was testing it on. 10/10 terminal, 0/10 for the locking. To account for this, you can simply press the locking tab press point out, then bend it once and it will snap. BUT YOU NEED ONE MORE STEP, you NEED to make sure to bend the locking tab itself up after snapping the press point, this is because the tab will snap just before the locking divot itself. So it's still there, but if you put it onto your switch, it will no longer have the thing for you to press to release it. That's no good