If I read everything correctly, you did not say what year your tow vehicle was.
I had a similar problem with my 2006 Ford F-250 Superduty diesel tow vehicle package and my 1968 Airstream
Tradewind wiring harness.
The F-250 has a "by function" 7 pin diagram printed on the protective lid of the hitch plug-in cover.
Do not try to match Fords color wiring harness to an airstream colored wiring harness, they most likely will not match.
Instead, match the functions by pin placement, recognizing that there is a mirror difference between the tow vehicle and the trailer.
I.E. if you look at the tow vehicle recepticale, pin 3 will mate with pin 7 on the trailer plug.