Sometimes, it's an electical problem. I had similar issues from day one and found that factory had wired my fresh water tank sensors in the wrong order. The other tanks were correct. That fixed the issue.
Mike & Pam '12 36RL, Kodiak Discs, 17.5" G114s H-Rated, SRE4000 w/HD Shackles, Joy Rider Shocks, Flex Air, 5.5 Onan, W&D, DW, 4 Scare Lights, (2) 6V Trojan T-145s; Progressive EMS-HW50C, Winegard DTV Sat, Sony/Denon 4K Home Theater, WiFiRanger EliteAC Pack, weBoost 4G-X Cell Booster.
2020 RAM 3500 Limited CC, LB, 4x4, DRW, Cummins HO, AISIN, 4.10, Curt A30 w/OEM Prep, Transfer Flow 70gal Aux Tank/Toolbox.