use a voltmeter to test each pin to be sure . most of the time a plug like that , the unsheilded wire is ground and the other one will be power . key on or battery hot . best to test it for sure . i would bet it is for a factory offer option , ie heater , radio something ac offers .
i just walked in the door from installing a 1200watt stereo in my xtz i ran all new wires from the battery i wired mine so i could turn it on without useing the key . so sense have the machine powered if im just sitting . just have to remember to turn it off. man this thing ROCKS now ! lol