Previous owner Neutral safety switch bypass

[Scottcoda]

Hey guys, I have been getting my new to me 68 2500 road worthy and my last tackle is the back up lights, Changed the bulbs, fuses, cleaned the light terminals and still no back up lights, so I thought I would start at the cab to see whats getting power and see if I can track down the problem, Well I found the problem right off the bat, The Neutral safety switched was bypassed by previous owner, the switch is still there just nothing connected to it and I can't seem to find anything that should connect to it. I would like to get the switch back in service, I know I can get a new switch(thinking the po prob bypassed cuz it is broken) and a new pigtail to plug into it but where do the wires go from there? Pretty much any info to get the switch back in service would be great.. All input welcome thanks guys!! Scott (68 gmc 2500 4.1 w/ auto 400 tranny)