Debrods, we too are experiencing a similar problem...sensor panel shows 2 grey water tanks and 2 black water tanks (1 grey water always reading full, while primary reads empty), but we can only find 3 pull handles (2 in the front access, but only one handle in the rear access panel, even though there is another spot for another handle)...questions to the dealership about it result in various responses, from shrugging of the shoulders to being told back bathroom holding tank is grey/black water combined, and when asked why we have 2 grey water listings on sensor panel, 'hmmmm...not sure.' As we were not given an owners manual when we purchased our 2014 Road Warrior 415, we're having to 'wing it' and try to figure things out ourselves.