2004 Cardinal black tank OUTLET location?

[steffco]

Howdy, Great forums and a lot of sage advice here.
MY GF just bought a used 2004 cardinal 5th wheel and the tank level says full. I can not get the black water to dump. I have located the correct valve since I can stop the snake from turning by closing the valve lightly.I have got most of a 25' snake to go up the pipes and retrieved a few wet wipes and feminine products and a couple of gallons of waste, now I am getting no more liquids.
My plan is to put some ridx in, let it soak for a couple of days then remove the toilet and try and snake and break from inside the tank. Anyone know where the tanks outlet is located? The tank appears to foamed in with a metal panel enclosing the bottom.
I have already learned the importance of water in this whole process. This unit is unfortunately semi permanently parked in a location with out a dump facility and the water will be shut off at the end of this week. I need to try and fix as much as I can before winter and then start with a new plan next spring.
Thanks