Black water tank won't drain? Valve stuck?

[jr2194]

I have a 2017 Fuzion 371.... I too have had problems with my tank valves. Spraying silicone lube down the cable and a little dawn with water in the tank helped all my valves to operate properly... however one of my black valves does leak by a bit so I installed a gate valve just before the hose until I decide to tackle the change out. I’m confused with you saying nothing comes out and it doesn’t fill up... on mine there is a second black tank valve behind the driver side tire. Be careful using the flush system without the valves open... there is a pressure check valve under the sink that may make a mess if too much pressure builds up. ... also if mine was new and having this issue and the dealer said September... I’d be calling Keystone! Good luck!