I have a small issue with my harness, car is 74 swinger and harness is xp777. Neutral safety switch, should there be only one wire or three. One goes from relay->NSS(center of course),then there is mention about GM style two gang switch, or if you use another type of NSS, connect purple wire to panel numb 3, blue goes panel numb 4 , another ends goes to NSS, it doesn't matter which connectors, so, outer connectors is back up lights, and center is ground, should there be three grounds or what?. Thanks....