looks like it goes thru the bulkhead to the ignition switch in start, you have three lines. Ignition 1 (run to ballast), ignition 2 (start to coil) and start (starter relay).

Ignition 2 is missing. It could be the ignition switch, the connector at the column, the bulkhead fitting or the wiring running between these points.

How much of this is factory wiring and how much is what you added in?