Need help reading backup lamp diagram

1972 Dart A904. I had the column lowered working on the horn stop lamp and time delay. Now my backup lights don't work. Everything else is still working. Fuse is good and so I'm sure I have a loose connection. What I don't understand is the diagram. Starting at the transmission switch. I see the B2B-188K terminating to a connector C and jumper-ed to D on bulkhead. But, now I'm lost because I don't see a connection on the next diagram. I'm guessing here but, does the ckt go through the column wiring or the other molex connector at the bottom of the column. Any help would be appreciated. Craig

Edit update went for ride hit brakes and horn sounded. Is this related. Also found better diagram and will review. Thanks