Well gosh darn. There were several good threads on this topic in the Truck Camper University section but many pictures have lost connection making it tough to use.
I used a 4 awg battery cable off the alternator and Negative off the Battery. I routed the wires down under the body along the frame rails inside split loom and zip tied to various points along the frame. I came up through between the inner and outer bed box panels and installed a 100 amp lift gate plug in the front left corner of the bed. I drilled a hole next to my 7 pin plug, converted from S&S 6 pin rectangle. I plug the lift gate for the connection and it works very well, mounts solidly. When you connect the DC DC charger, you don't want any other truck battery connection to the camper batteries. Charge with the DC DC only and nothing else. If you connect the stock wire to the TC batteries, you will be confusing the system with a different voltage and you don't want that. You can use the old wire for a trigger wire to the DC DC unit since it comes live with the key and will activate the DC DC charger.
