Bought 2004 Jayco Granite Ridge 3100ss last fall.
Been wondering about the white box in the back storage compartment.with a black hose coming from it. Finally, took the self tapping screws (10) off the top lid to find another battery in the white box.
So I guess I have two batteries hooked up in parallel (sp) I guess this is a plus for me. I checked the water and it is good. I then traced the the wires and found out them to be hooked ti the other battery. Da! The black hose is a vent for the battery.