The connection from rear where water hook is should apear in cabinet above pass. side and would normally go into a cable switch box for tape player and TV locations.
If this is missing you may have to take off face plate to locate you cables.
Should have one from TV ANT amplifier, rear TV and front TV from sidewall box of Tv housing. Plus from tape player if you have one.
Welcome to the Newmar forum & irv2 by the way.