72 Swinger - Some wiring questions.

On the cowl device, get into the FSM in the emissions section. So far as anything connected back to the bulkhead, get into the diagram and find out specifically what pins it connects to. That cowl device I believe is part of the NOX system

Aftermarket diagrams, NOT in the FSM, are sometimes easier to follow, but often leave out options and connectors, as well as not diagramming connectors as to shape for ID

Also EVEN THOUGH it is quite different, you might try going to MyMopar and download the 73 manual, as the wiring diagrams are set up differently, more detailed in some respects--and--back in the pages beyond each diagram are charts diagramming specific connectors as to shape, etc. Again, that year is DIFFERENT, but some of these odd details might "show up."