I assume you don't live in North America.................
Last model year of Rangers here was 2012
T6 or international Rangers are different than what we see here, they are slightly larger and get the turbo diesels.
But to answer your question generally...............
The 2 reverse light wires will be on the transmission, there will be a 12volt wire that is active when key is on, the other wire goes to the reverse light bulbs, the transmission switch connects these two wires when shifter is put in reverse.
Trailer connector may or may not have reverse wire, if it only has 4 wires then no, the reverse wire will not be there.
Not sure this will help you since it is for North American Rangers, but have a look here:
How to wire up the lights & brakes for your vehicle & trailer
Reverse lights are also called "back up lights"