I the case of 7 pin connectors
ALL Grounds (lighting- electric brakes- charging) use same ground ( pin #1)on Trailer... I always bond the ground ( pin #1 ) to chassis of trailer AND run it to battery and to lights if lights are mounted on insulated surfaces.
Pin # 4 is standard for any 12 volt supply through 7 pin connector...


Keep in mind the popular 7 pin connector on travel and utility trailers is the RV style "blade type" connector, the 7 pin "round" style connect is commercial truck and equipment and wire differently...
A relay under control of tow vehicle is a good idea to keep from drawing down TV battery... Also Diode isolator may work, or simply remembering to unplug trailer connector when parking...
IF 7 pin connector is part of standard wiring package on TV it may or may not have relay control (my Chev PU does not) but if its a factory installed harness and connector it will probably be fused.... MY Chev PU is fused, but fuse was not installed from factory (40 amp - check owners manual)...
Dale
Lives his life vicariously through his own self.
Any statement made by me are strictly my own opinion.
You are free to ignore anything I say if you do not agree.
