MAD electrical upgrade for 1973 Dart

So, I traced the wire that goes to the neutral safety switch. The 3 wire plug is not even hooked up to the Switch on the Trans. Previous owner must have grounded it somewhere and after moving things around the connection got fixed. So now I can start it with the ignition switch. Now I just need to repair the wiring for the Neutral safety/Back-up light switch and install the Ignition switch into the Steering column. After reviewing th ewiring diagrams, I can't even see how the Signals/Reverse lights are even working.