Are you talking about you cannot dump the gray tank? Or the water does not go down the drain?
And how do you know it is full? Is it coming up in the floor of the shower? That is generally totally full.
If this is the gray tank, when you pull the sliding dump valve, do you feel the normal drag when you pull it open? If the valve is open and the tank had water in it, it show come flying out. You should be able to feel the drag opening and closing the slider valve. This seems to point to the valve not opening or you have a really bad build up inside the tank covering the opening.
Hope this helps
Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC
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