Black Water Valve with a wire pull opener, problem

I have a very difficult Black water valve. I watched video and viewed responses concerning these type of problems on RV.net. My valves are the type that have the handle that engages a wire that pulls the actual valve underneath the belly of the rig. I have already removed the underneath rig covering exposing the piping and valve.
Thinking this situation out, Iam not sure if the wire is the problem or it is the valve itself that will have to be taken apart. Even with the gauges showing empty and the valve showing opened, I am in a CG starring straight up at the valve. I just don't get that warm fuzzy feeling taking apart that valve. Has anyone had this same problem? How did you resolve the problem?