It would help to know what year and style of camper you have to answer a question like that.
Wiring for 5th wheels is slightly different than travel trailers and WAY different for motor homes.
In general for trailers, there is a junction box where the cable from the truck enters. There are 4 wires that come out of the junction box that handle your lights.
Yours may be like mine a ribbon cable using NON-STANDARD colors (!) with a white (ground), Green (running lights), red (left turn/STOP), and Brown (Right Turn/Stop).
I will try and get a photo tomorrow.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW