grey ater dump valve 2009 challenger

[821mark]

hi, can anyone tell me how to locate my grey water dump valve on my 5th wheel 2009 challenger DBB. I cannot close the valve. it is stuck in the open position. I need to either repair or replace it and do not want to have to remove the whole underbelly. thanks in advance for any help or comments.

[hankpage]

Is it possible it's just frozen??

[821mark]

It gradually got harder and harder to close until finally it would not close at all. it is a cable actuated dump valve. thanks for your quick response.