Try cutting off the cinch clamps that are on currently and replace with screw drive type hose clamps. Hard to tell what fitting type in the picture but most RVs have braided tubing like you have incorrectly used with PEX fitting. This combination is prone to leaking because the braided tubing has a larger ID than PEX tubing and the cinch clamps used will only tighten to a pre-determined point. It is unlikely the factory would install any shut-offs valves although they are easy to add if desired.
Seasonally in the Grand Marias, MN campground
On the beautiful shores of Lake Superior
2012 Ram 2500HD CTD