Good catch! I have a Blue Sea fuse block in that location, too. For performance reasons, I would still eliminate that section of 16 AWG wire on your rear 12V plug. In your pic of that plug, it looks like the connections are the quick disconnect (clip on) covered with heat shrink. If so, you could cut the heat shrink off with a razor blade & unclip the 16 AWG (remembering the polarity) and cut them off at the end of the 12 AWG. Re-terminate the 12 AWG proper size clip on terminals and install them along with heat shrink on the plug. It looks like you have sufficient length to do that and everything you can do to improve that 12V plug will pay dividends down the road.Just to keep this thread up to date with the ARB plug option. I ended up finding out that my power wire was run to a starter solenoid in my diesel swapped rig. The previous owner had put a LOT of aftermarket power wires on there. The terminal was under tension and the housing had developed a crack, which caused poor contact inside the solenoid. (burn marks) When I traced the power wire back to the solenoid, I tried to tighten the connection and it came off in my hand......
I rewired all the other wires to a Blue Sea fuse block I had in the garage. (Sorry for the bad picture).....
The rear outlet now seems to be working. The fridge kicked on using only battery power. I'll keep tabs on it. Also, the ARB cord works, if I push and hold it in the outlet. So, my thought is that the ARB socket along with the ARB cord might still be a good option for me. I'm going to run what I have for a few days before making that call but I wanted to update anyone reading this that the ARB option is not dead.