Where are the purple 20 wires for turn signals?

[BlackTopMotors]

OK,
I am trying to wire my front turn signals and front markers on my 71 C20
I found two brown wires one for the alternator and one (they look the same) for the markers (from fuse panel/engine harness in engine compartment). (black wire grounds to sheet metal...tested and working just like the back markers).

I also see the light blue and dark blue wires (as per schematics) but no purple20??? I have tried grounding/running one of the wires on the turn signals to sheet metal and they function as turn signals but no parking lights/running lights? Anyone else run into this?

I can't figure out how to get the turn signals to function as both parking lights and turn signals when the light switch is pulled out partially (or is that just how things were supposed to function? Any help would be greatly appreciated!

Roger