[webslave]

You may have two gray tanks if it is like my 318SAB... The bathroom gray tank valve is located next to the black tank valve, but... The kitchen has its own gray tank and its valve is located just in front of the forward wheel, up under the edge of the trailer. There is a long pipe tucked under the trailer that carries that gray water down to the common outlet.

Not familiar with your particular trailer, but, on longer trailers it isn't uncommon to have another gray tank and valve located elsewhere, as my 318SAB does.