1968 Dodge Dart Engine Bay Wiring Fix Questions

There's another member discussing this exact problem right now. Connects to the connector inside the car, which would have connected either to a column shifter reverse switch, or by extension to the console shifter (automatic). This is a half moon shaped connector. Feeds up through the wiper section of the bulkhead connector, from there down the engine bay side of the firewall to the 4 speed switch

Link he posted to the switch

1968 Plymouth Barracuda Parts | MD4520 | 1967-68 Mopar A/B-Body Back-Up Lamp Harness | Classic Industries

Another thread

1968 4 speed reverse light wiring routing

and these two

neutral safety switch - 1968 383 4spd Barracuda

back-up lights - '68 4spd barracuda