Wiring turn signal question, purple wires

[Peepaw]

Good afternoon guys.

I have a question regarding my 72 C10. I am rewiring entire truck, and the diagrams that have been posted have been HUGE help, but I have a question regarding the wires coming from the turn signals.

The purple wires go into the plug/junction box at firewall.
then....they come out on other side as one brown wire? And then it goes to fuse box?

Then the dark blue wire and light blue wire goes into the "u" shaped connector under steering wheel. Then they go into the connector that plugs into instrument cluster.

What has me confused is there is really not a clear (that I have been able to find) explanation for the connector at instrument cluster connector and wiring for blinkers/hazards and the relays assocaited with those. Anyone have a picture of wiring for that?

Thanks, Derrick