Help, 72 duster NSS/Back up light harness hook up.

I don't have a 3 prong plug. Here's where my other 2 wires plug in.....

The black wire with white tracer plugs into the top left of the headlight harness. The solid black wire goes in the bottom left of the headlight harness.

My 72 is an early build August 71, and does not have a seat belt warning light in the dash. Maybe that could be the difference :scratch: