The 1954 truck wiring harness was plastic/vinyl sleeved/coated (cloth covered/sheathed wires ended in 1952 trucks, I think).
Two wiring diagrams are attached below. low-res and hi-res
I think you will see that the front parking lamp wire in the main harness is purple. The parts of the harness that splits off to the front lamps/lights and goes to front-lamp junction "strips" on each inner fender contains the purple leads. The color or the parking lamp lead from that junction strip to the lamp is "natural" - a light tan, as I recall.
