So I ended up borrowing a higher wattage iron, getting flux, and sanding the wires. I only got partial tinning. Sand paper had more effect than flux.
It didn't tin all the way to the where the conductor and jacket line is. I think the jacket is melting and giving off vapors that prevent tinning all the way. I tend to think the wire was not meant to be soldered, only crimped? It's super frustrating as I touch the wire with iron, and opposite I touch the solder to the hot wire. The hot wire melts the solder and it just runs off.
to any extend my repair was pretty amateur and I need a second round to cut the wire back further to a straight section inside the harness raceway. My current patch is in bending and is not a long term fix. The car has been driven for the past week so it works. I was also able to clear the DTC codes by pressing the power button 2X without foot on the brake pedal. This puts it in "on mode" or whatever it's called but doesn't fire the engine. As long as the engine is not fired, you can clear DTC codes. You can't clear DTC when the engine is running or so if the car is in accessory mode.
no DTC codes have returned since.
crappy fix. Insulation jacket is melted. Not tinned all the way.
heat shrink on but patch is in bending.
i will.have to cut the wire further back to a straight section in the harness raceway and patch again and replace connector and pins.
lastly used high temp aerospace kapton electrical tape. It's not very flexible but this stuff is good for over 200 deg C.
after my crappy fix, I consulted one of the electronic techs in my plant. He recommended me to use water proof crimp and heat butt splices. That's what he uses if he can't get something to take solder. I'm not sure if it'll fit into the wire harness races in in the car, but it's worth a try.
Rat has been an absolute pain. I also spent much time sealing off the attic gaps as it was also climbing into my attic, and I set traps and bait. The rat eating the car was really unexpected. It does eat many of my veggies and fruits in the garden.
It just bugs me that this is new and has less than 12k miles yet I'm having diagnose and fix this. It's not Hondas fault but it just irks me. Perhaps if the car was at 150/200k miles I would not be irked.
Years ago, on my one of my Hondas had a mouse that kept on getting into the cabin but all it did was walk around and poop and never chewed on wires l. Mouse trap took care of that one.