I have removed the factory hard center tank (2006 SANTE 220 Limited) and replacing with at 500lb fat sac. Does the senor gauge from the tank need to be wired a certain way so the pump will run in reverse to empty? The pump will fill the fat sac from the control panel with no problem, however, it will not switch into reverse. The light on the control panel flashes like it is in reverse but the nothing at the pump? I am guessing that the has something to do with the fill/empty senor that used to be in the hard tank?