We have a 2017 25.2 and you have to open the couch just right then contort yourself (really) and look under the wall toward the bathroom. They are there. I know as I found both valves to be in the wrong position from the dealer new.
Chris & Dorrie & Pups
2017 Thor Vegas 25.2 w/Toad - 2014 Nissan 370Z
Mods - Safe-T-Steer - Roadmaster Sterling Towbar - Tow Defender - KarGard - Thermopro In/Out T-Stat - SS Kitchen Sink - Garmin RV770 - Propane Tee Grill Adaptor - Custom Center Console - Oxygenics Shower Head - 10" Rear View Safety Monitor - Verizon Hot Spot - Radiator Guard - Sumo Springs - Cylinder Locks