After you repair or replace your RV water pump, there won't be any water in the chamber. If you try to turn it on at this point, it simply won't pump water. That means you need to prime your water pump. You may also need to prime your water pump when winterizing your RV and then in the spring as well.

Furthermore, if your water pump continuously runs when not in use and you have confirmed that water is available to the pump you most likely have a pressure switch issue. Another Indicator that your water pump may need to be replaced is if it begins to leak.

Generally speaking, if your water pump is cycling on while you are not using water, then there is either air getting into the pressurized plumbing system or water leaking somewhere. An air or water leak would cause the system to lose pressure resulting in the water pump needing to cycle to restore the proper pressure.