Check to make sure the cutoff valve hasn't lost a wire, it needs both to close the contacts, and open the valve. That could be where your grey wire goes. Also, check to see if the valve is getting power and ground, so it can open. If everything is hooked up, and it isn't working, you should probably take it to a place of repair.
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.