Resurrection of the old Reverse Light Thread

What do you mean, "several wire pigtail?" You talking about the wiring harness?

The stop / tail lamps are two lamps in one, and have two contacts plus the shell which is ground. So one wire in the harness is the two tail lamps, two more wires are left and right stop/ turn, and the last one would be for the reverse lamps, the sockets of which are SINGLE wire plus the shell