The way I remember the wiring, (it's been awhile), the wires follow along the outside edge of the floor pan, held by a couple of metal clips along the way. They then enter a tube that goes between the axle and the pan. There is a small bolt that holds the tube to the pan, and the other end goes through one of the axle housing bolts. Then there is a plate that covers the rear axle, held on by 2 screws, the wires run behind that and come back out near the fender, where another clip holds them. If you have original wires, there is a disconnect at the fenders, and another near the front of the floor pan. At some point they changed the design of the tube at the rear axle, and it was incorporated into the plate that the screws hold to the axle.

I'm not sure if this is much help... and it's just from memory. I'll check when I'm out in the barn later today. We're at 5 inches of the white stuff and counting.