[Just-in-credible]

The first thing I jumped back into was the transfer case writing. It was driving me absolutely bonkers. I went on all data, I got the schematics, and I went wire by wire through the entire thing. I had a few issues. The first issue was that I did not have the serial data wire hooked up. No big deal…I just jumped a wire from the serial data wire in the TCCM into the OBD2 port, as this is where the serial data goes. I wasn’t sure if I had life or not yet, but now I had some sort of volatage happening in the TCCM, where before, it was all just dead.
So I knew I was on the right track. I had everything wired temporarily and I had assumed that things would work if I had power to the unit and the ignition was on.
Well folks…this was the main problem the entire time. As a complete coincidence, I fired the thing up to move it so I could sweep the floor…and to my complete and utter surprise, the switch came to life and the damn thing started working.

So lesson learned… for anyone attempting this same thing, the TCCM needs data that the engine is actually running before it will do anything. Having the ignition on is not the same thing, and you will beat your head against a wall for days on end trying to figure out what you did wrong.
So after this, I tucked all the wires up as tidy as I could, and I zip tied the original switch under the dash. I will clean this up eventually, but for now, this will work.

A lot of the wiring has been this way because I need to figure out what needs to go where before I can clean it up and tidy it up.