well, as mentioned at the other thread... if you have two wires mismatched ( one on each side of firewall ) you actually have at least 4 wires mismatched... at least two at each side of firewall... Maybe even more, because there is no way to just get one wire mismatched at each side.
The good on this is you are on the track without ( apparently ) a bigger damage.
That red wire seems to be the batt wire, the one which should get the fuse link. Hence why you don't have ammeter reading. The ammeter is actually a batt status gauge ( geting charge or discharge ) depending on alt capacity.
The violet wire is the temp sender wire, which handles negative/ground sourced by the sender, which even with low resistance reading ( low temp ) around 70 ohms will produce a short (Is like a Bulb, which is a controled short) somewhere along the line... so that explains the fuse link fail... and some other fails per what I have found on your other threads.
Now, which other wires are crossed? maybe just those two on the cab side mismatching the two on engine bay side? Or some other?