[Pmedic4]

Hey, did the same thing. An hour and 1/2 walk through, and just forgot about the 2nd GW valve. We don't have the fancier Montana control panel, and 2 underbelly outside valves were easy to see, while the 3rd ( 2nd GW) value was hidden up on the frame, right in front of the wheels, and the black handle was right next to the frame so it was almost invisible.
This old man crawled everywhere under that 5ver to find that sucker!