A breakdown of either the power or ground wire downstream of that 2 pin connector, will of course cause the same problem. With the 2 pin connector hooked up (an parking lights selected on), getting either a good power and or ground return reading at the lamp sockets, would help you determine if one or both wires are in trouble. I can't tell you to do this, but if the stationary section of the wiring harness looks rock solid passing thru the trunk lid, it almost has to be within the rubber transition boot. If I had to T/S this, an found that I had enough access to stagger cut the 2 wires downstream of the boot, that's what I would try for. If one or both wires proved out as faulty at that cut point, you could then attach an back pull 2 fresh wires thru the rubber boot. Then stagger cut the upstream wires from the 2 pin connector at a convenient location, then splice an wrap up everything as necessary.