sprinter 302rl 3rd gate valve?

[moose308]

Any idea what the 3rd gate valve by the black and gray water valves is for?

[JRTJH]

You should have 3 valves, one for the 40 gallon black tank and one for the 40 gallon gray (shower) tank. These two are inside the convenience center. There is another valve somewhere adjacent, it is for the kitchen sink gray tank and also is 40-43 gallons.