Dash and turn signal issues
I may have some hard news for you, and it goes right up to the top of this post
You say you have a 73 column? The ignition switch is ON the column? Is it being used? Where is the switch that operates the car? 68 would have been in the dash to the right of the column. 73 would be on the column like "more modern cars"
That connector you are holding is for a column ignition switch.
As I said before, you have an abortion. You are going to have to get documentation, drop the column so you can remove the dash, and get in there and check and rework and repair the wiring.
The SECOND problem you may be facing is general wear and tear..........problems in the bulkhead connector, the headlight switch (unrelated) and it's connector, and the ignition switch (unrelated) and it's mating connector. What I mean by that is that you may have OTHER unrelated problems in the harness not related to having "mixed and matched" parts and pieces.
Let's say, example, that the dash mounted ignition is what "operates" the car? You take that out and examine it, and it appears NOT to be "hacked up" and spliced into the harness. This would indicate to me that you PROBABLY have a "mostly" 68 harness and that someone did the MINIMUM work to "throw" a 73 column in there to get it installed, and all you need to do is properly interface the 73 column wiring with the 68 harness.
Your video does not show us much. What I need to see is "what they did" at the column wiring. On a late model column (ignition on the column) there will be TWO wiring pigtails / connectors coming out of the column. One for turn, the other for the ignition switch
Again, that photo is for an ignition switch connector. Is that the under dash harness end or the column end?