I’ve noticed that when towing the trailer with the gas fridge on, the trailer battery loses voltage over the course of a day servicing the 12v
requirements of the fridge.
I had assumed that the 12v
pin on the plug that attaches to the truck would keep the trailer battery charged but this does not appear to be the case.
The “schematic” in the owners manual, which really is just a helpful diagram labeling the wires in the 12v
fuse box, shows no indication of a connection between the 12v truck wire and the trailer battery. I’ve taken voltage readings with the truck connected and not connected and I cannot see a difference in measurements.
Is the connection between the truck and the trailer battery non-existent? Or is it hidden in the wall and not documented in the manual?
FWIW, both the truck and trailer batteries are new. The truck charging system is working fine. The modern 3 stage battery charger in the the trailer is working fine and charges the battery correctly when the trailer is plugged into 120VAC. There are no modifications to the fuse box wiring by previous owners. And the fridge is fairly new.