Thanks a lot, that was it. This is the part I'm missing in the list of my diagrams. I like your source better - much more readable than mine. Where did you get it? (EDIT: Found it - it's Mitchell 1.)

So simply saying the towing socket turn signals (pin 1 and 7 on your diagram) come directly from flasher. So no magic here. I did not know that as "Trailer Tow Cuircuit" does not exist in my docs. I guess I need better manual.

Now answering other questions, I'm taking this car to Europe (yep, I love it so much I can't live without it ). So my questions are completely not related to US standards, but I'm trying to prepare what needs to be done to not get into trouble with EU police.

As for driving and towing in USA there is no brainer with this truck as like all you pointed out T4R 5th gen is already ready for towing stuff (I used 4-way connector for U Haul trailer and rented log splitter from Home depot. Worked like a charm.