If you have a modicum of understanding of how towables are wired, it is an afternoon's work to add a 4-pin connector to the taillight feeds. Probably only a matter of matching colors.
If you don't have a clue on how the tow and trailer's electrical systems interact. You'll spend 2 days not understanding someone who does.
You've got 3 hots and a ground on a 4 pin setup.
A) Running Lights, usually brown
B) Left Stop/Turn (Yellow, IIRC)
C) Right Stop/Turn (Green, IIRC)
Although I may have yellow and green reversed.
You'll have to unbolt the tail lamps from your TT. Find the 3 feeds and fish wires down to your new 4-pin connector. Find a local ground and you are all set.
Then the problems start. Blown fuses, flasher too fast or slow. If the line is not fused, a damaged flasher or letting the smoke out of the wires.
Read up on trailer wiring, turn signal wiring and understand how to use a VOM, DVM and a test light.
Also read about how adding a relay will reduce the amount of current one circuit has to carry.
Once you understand all that, you'll have no trouble with your endeavor.
TT 2015 19RD "TheJayco"
TV 2003 F-350 "Montblanc" - Housebroken chore truck
Sitting in The Cheap Seats.
And proud of it!