NSS is in the trans..and attached to the valve body...
went the trans is in neutral and park, it provides a ground to engage the starter relay switch..
dont know which one you have...if it is a 3 post switch...located on your trans..near where the shifter goes into the case....the center post is for the neutral safety switch...the wire goes to the starter relay switch on the G terminal...G for ground...
the other two terminals on the NSS is for the back up lites..
