I have a '98 Allure, so we may have similar systems. There is a diverter valve handle in your water bay near the sewer dump. When this valve handle is turned open, the shore line water supply is diverted to your fresh water tank. It should be closed if you want to use shore line supply water and not tank water via the pump.
The pump issue may be a result of the above condition, or it sounds like either your pump is failing or your friend left an outlet valve open, thus preventing the pump from applying full line pressure to the water system. Check both the inside shower and outside showers to ensure that the hot/cold controls are both off. Sometimes users turn off the water at the shower nozzle end and not the main valve. This causes problems.
1998 Country Coach Allure 36' (CC# 30146), Cummins ISC 325
2012 Jeep Grand Cherokee Overland, Roadmaster Brakemaster & Blackhawk