Odd parking light

[Moonpie+RC+Old Fords]

Long story short, my recently rescued F100's under-dash harness was FUBAR'ed, and in order to make it street legal, there was no way around installing a new harness. As I am a restorer on a budget, I can't at the moment afford a brand new harness, so I got the next best thing: An under-dash harness from a '70 F100 in the junkyard. As much as I hated to, I had to cut the harness (of the junker) just after the instrument cluster (before the heater/right side lights). Much to my surprise, almost everything worked after 3 1/2 hours of surgery. One thing, however, has stumped me (which isn't terribly hard to do); allow me to explain:

My truck is a base 1971; the donor truck is a 1970 Ranger XLT with several options that mine does not have (radio, cab lights, cargo lamp, gauges instead of idiot lights), so obviously, I have a few wires leftover that do not belong anywhere and are, for now, just "hanging out". I got my instrument cluster (with lights) working, as well as everything EXCEPT for the RF park light. With the headlight switch pushed in, and KOEO or KOER, the RF park light is illuminated. When I pull out the switch one (to "park"), the LF light illuminates, and the RF goes out. With the switch pulled out all the way ("lights"), both park lights light up.

To keep things clear, the instrument cluster lights work (properly), dome light, both headlights, brakelights, all turn signals, and all markers except for the RF light. I am sure that somewhere I crossed wires, and after looking over the wiring diagrams, I am stumped thus far. If anyone has run into this issue (not likely haha) or have experience with this sort of anomaly, any help would be greatly appreciated.

[68RGR]

On your truck, should the parking lights be on with the headlights or not?

Do the front turn signals and emergency flashers operate properly?

Did the parking lights operate normally before you changed out the wiring?

If you are uncertain:

Have you checked to be sure the correct bulb is installed?

Have you checked to see if the RF parking light socket is properly grounded/wired? You should be able to compare it to the LF.

[Moonpie+RC+Old Fords]

In order:

the parking lights should be on when the headlights are on (switch all the way out)
all turn signals and emergency flashers work
the park lights did operate normally before I switched the harness (one of the few things that did)

About the wiring of the park light, according to the master diagram and lamp diagram, the LF park light has a separate ground (like the headlight) but not the RF, unless it is implied and I just can't read (an equally plausible explanation). I had every intention to go investigate the issue further today (take off the whole grille to see of there is any wires "hiding" from me), but until it stops raining, I am stuck inside re-reading wiring diagrams. I did not compare the light bulbs, so that's something else I will look at when I dig deeper.

[Moonpie+RC+Old Fords]

Update:

After approximately three more hours of testing, tracing, and splicing (repairing) wires, the solution has been found: When I originally crimped together the two harnesses, I inadvertently (and stupidly, I might add) crossed the heater motor switch (circuit no. 399) and the headlamp switch-to-R signal wire. In both of the harnesses (original 1971 base model and 1970 XLT), both circuits use brown 14g wire; even though I couldn't find reference to any such " BR 14g headlamp switch to R marker lamp" on the site (the only brown 14g wires are heater motor switch and light switch to rear lamps, that I have found, while the R marker/turn signal wires are WHT/BLU 14g and BLK/YEL 18g), so still confusing, but problem solved

[Moonpie+RC+Old Fords]

Thank you 68RGR for suggesting to re-check the ground; it was that line of investigation that led me to discovering the crossed wire situation