Knew it would happen and it did!
Macerator hose leaked. No valve to block in macerator and use bypass hose! Luckily it was only a pin hole and I could press the hose together and dump the tank. If it would have been a burst I would have been ticked off even more. Called Thetford and got another hose. Went to the hardware and bought a 1.5 close nipple and a valve. Problem solved. I guess Jayco doesn't have an "engineer" on their sewer systems.
2016 Seneca HJ