Inside the passenger compartment just before the engine gauge feed plug goes through the firewall, there will be a male and female bullet plugs with red/blue wires on the underdash harness. These connect to the NSS/BU harness if automatic and backup lights. For a manual car, simply mate the male and female bullet plugs together on the underdash harness. For manual cars with backup lights, a separate backup light harness without NSS was used, but stayed in the passenger compartment until exiting near the shifter hole in the tranny tunnel.