Back up light wiring?

In the begiining the reverse lamps were in the cabin on the shifter. Since column shift was the standard the switch was placed on the steering column. Its difficult to see since it is on top of the column about half way down to the floor. Grey colored connector w/ 2 purple wires. When they added optional floor shifter they added a extension cord from that connector to the switch mounted on the floor shifter.
People will often refer to the 3rd bulkhead connector as the wiper motor connector. That's only because it didn't have any other wires/circuits in it but guess what?.. when the factory decided to move the reverse lamp switch out of the cabin and down to the trans they used 2 of the extra/unused ports in that 3rd bulkhead connector. So it wasn't a wiper motor only connection anymore.
If you have a later model trans that employees a 3 post switch all you need to do is what the factory did. find those 2 purple wires , disconnect them from the connector at the steering column, route them outside, tape them with that single brown wire going to the trans mounted switch and hook them up. Done