Hi Randy,
From your discription, it sounds like the blade assembly is not fully closing. It is not unusual after 16 years for a wad of toilet paper to get caught between the 2 seals just as the blade is closing. Unfortunately if that is the case, you will need to access the valve, disassemble and clean out the debris. Another possibility could be the actuator is worn out and not providing "full travel". Either way you need to get into that area and take stuff apart. On my coach, I needed to remove the rear gas prop to get the metal panel out to access it.
Regards, Fred