Actually from what I can find in the wiring diagram, the black wire is the ground for all so it would definitely affect the wipers, defroster, and washer. Why send 2 wires all the way to the very back plug if they are not required for something else as well. A simple computer input could otherwise do the same.
2008 Black and Khaki Sahara Unlimited Trax-Lok rear diff. 3.5" Rock Krawler fr springs, rear TeraFlex 2.5 BB, 37x12.50x17 Pitbull Rockers on ProComp 7069 Alloys, AEV Prem Bumper ETC..