Ford has provided the wiring for a trailer on the F-53 chassis since at least the early 2000s.
The Ford wiring ends in two connectors at the rear of the frame, usually inside the left frame rail. Ford provides the "coach builder" with pigtails to plug into the connectors. The "coach builder" decides which wires to extend to the trailer hitch connector. It sounds as if on yours that Forest River (the "coach builder") extended only the
LEFT TURN/STOP (yellow)
RIGHT TURN/STOP (dark green)
PARKING LIGHT (brown/white)
wires, so these are probably unterminated on the pigtails:
TRAILER ELECTRIC BRAKE (dark blue)
BACKUP (black/light green)
Note that Ford does not provide a 12V charge line on the F-53 chassis. If there is one, it is run by the "coach builder." If yours does not have one, you'll have to run a cable for that purpose from the coach battery to the new hitch connector, making sure it is of adequate gauge and properly fused at each end.
Here's a page
to which I often refer when I want to know about connectors, pins and signals.
Note: While there's nothing incorrect about a 7-pin connector with round pins, the "RV standard" 7-pin connector uses flat pins.
See also this post
I made, with more information, including diagrams. And this post
, although some of the information is repeated.