How many of us are there? Owners of Dodge based RV's?

Thanks, HItech
The john has a single knob. I mean to go out and try more than just one twist and release. It may fill if the release is slow (or paused). The only thing I can think of, is that the knob once released slowly to fill the bowl and has since worn out and just snaps back to close. (thus allowing only a very short time for refill.)