I am not familiar with your model, but you might want to check to see if you have a fine-gauge debris screen somewhere in the transmission line. If you do, it might be gunked up. Believe it or not, those can get fouled to the point where they block water flow.
Here's what ours looked like (this being on the fresh water tank line, not the city line). We didn't generate the poor maintenance conditions that led to this. We bought our rig used, and it came like this. I shudder to think what had been in those lines.