3 switches for pump...then it has a latching relay
Pump switches connected to 'ground' so they make up circuit thru latching relay
Locate latching relay and check for DC to it
Fuse could be at pump or at relay
As for fresh water filling while using city water
Either the 'Fill Valve' (if used) is leaking thru
OR
Pump Internal check valve is not closing and allowing backflow thru pump
Is it time for your medication or mine?
2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31