Recently purchased the motor, trans, transfer case, and wire harness from a 2012 silverado to go into my 2007 silverado. Everything has been swapped into the truck in place of the old 5.3. Everything bolted up and plugged in except for a wire or two to the transfer case.

My question is how can a plug-in on the harness not hook up to the transfer case it originally came with?

Also, what would it take to fix this and would it only take a new bcm and a tune to get everything including the 4wd to work?

The garage is completely lost so any help is appreciated!