This is just a guess but try looking inside the RV near the outside water inlet. Looking at the floor plans on the Jayco site, it looks like that would be near the bedroom wardrobe that is adjacent to the shower. Look in the back of the wardrobe and see if the water pump is there. Or, if the water inlet is further toward the front of the RV, perhaps it is under one of the dining area seats.
In our 2010 Jayco G2 29RLS the water pump is inside the trailer adjacent to the exterior water inlet. Specifically, there is a built-in shelf between two recliners and the water pump is inside the enclosed shelf.
Call your nearest Jaco dealer and ask for the service manager. He or she can tell you where the water pump is located.
Emeritus Member of Jayco Owners' Forum