My 92 is a 27-footer, so the valves may be in different spots. Mine are accessible through my rear-most external storage compartment (which is also under my bed). The valves are next to the pump. 1 valve controls flow to drain the tank, and I can't remember what the other valve does. There is also a typical twist-style valve that allows me to isolate the tank and another that allows me to control flow to the external shower.
Let me know if you need more info and I'll try to run it to ground for you.
Tom
