You should have a 135 degree barbed plastic fitting stuck in the open end of the vent hose to prevent water from running along the frame rail and into the hose. If not, reposition the hose so the open end points down and/or back so water will not get into it.
'07 Winnebago Journey 34H, ISB-02, MH2500
Toad - '08 Ford Taurus X
Blue Ox, Aventa
US Gear UBS