My vehicle came without any trailer harness, I rigged it up myself. The charge line is a dedicated 8 AWG wire that runs from the battery to the 7-pin connector, through a relay and appropriate fuses.
I have 2 items wired directly to the trailer's battery (they bypass the master switch). First, the breakaway switch for the brakes
, so the brakes
will activate with breakaway switch pulled even if the battery master switch is OFF. Second, my solar
panels also bypass the master switch and will still recharge/maintain the battery when the trailer is parked with the battery switch at OFF. The solar panel
controller has its own switch that allows me to cut it off if I need to.