Land Rover Repair: 1996 RR 4.0 - Trailer Hitch Electrical, rear bumpers, test light

Question
Long story made short.....After an accident my rear bumpers were replaced. Body shop provided the parts kit YMJ500131, which has the convertor, however, the body shop installed the plug that came with the bumper. I am now in need of a plug with the three pigtails, the one installed only has one. LR dealer wants my to buy the entire kit for $300, I only want the correct plug. I am now looking for wiring diagrams to see if I can rewire it to make it work with the convertor installed but cannot locate any diagrams for the plug or the convertor. Suggestions? Thanks!

Answer
I can't help with a diagram . . .if that truck was here in our shop we would just puzzle it out with a meter or test light.

I think you may be able to buy what you need from Atlantic Brisith, though.  They have a considerably less costly trailer kit that's right for the US market