Under Dash Reverse light wiring?

What year/ model we workin on? The bulkhead connectors change over the years.

Documentation on this is poor. I found it on one diagram, all it showed was one wire coming out the the bulkhead where the reverse lamp power comes through, with one wire going to the lamp and a note that said "not part of instrument panel wiring." Of course they COULD have told us WHAT PART of WHAT WIRING is is PART OF, but then, hey, it's Mopar we're dealing with!!!!

This is what the 70 Belvedere shows. This appears to be an added wire, simply taped to the outside of the main harness coming from the bulkhead That's the wire marked "V cavity Z"