Neutral safety switch harness question specific to 1974

yep , At one time the reverse lamp wires were inside the cab. The neutral safety wire didn't go into the cab. Just a single brown wire went from neutral safety switch to starter relay. When all this changed they routed the wires through previously unused ports of the bulkhead connector.
So that 3rd male connector isn't really a "wiper harness" connector. It was called that by some because it had nothing more in it. Neutral safety is brown. reverse lamp wires are purple/violet.If those colors never changed, That's what you find in the dangly add on at bulkhead.