Just an update, I changed the transfer case fluid today. It did have a dark gold to light brown color, but it didn't look terrible. It only held around .7 of the liter bottle before it started running out the top hole so I guess I didn't get all the old out but enough to refresh it. I will say the top fill hole is in a terrible spot for just about anything....lol

Once complete, I reset the fault code and updated the adaptation for the tc. I drove it all around this afternoon and all seems to be back to normal.

With that done, I'll try to figure out what sensor is needed for the HVAC fault.