I agree on the 12v plug.. is the plug hot at all when you remove it from the socket? At the height of my Edgestar days, I could burn my thumb on the plug.. I ended up using a trailer wire harness and connection instead, with much better success and no appreciable heat loss- just one step away from hard wiring the thing.
The plug on my Engel is of much better quality though, and I'd presume your ARB would be similar.
82 fj40, 99 uzj100, 06 gx470
97 DR650, 05 525EXC, 06 TW200, 89 TW200, 09 TTR125, 07 TTR90, 07 CRF50