Ok, short story long...
Found the pump. Under a box next to the bed. Had been accessed before. Lots of spare hardware in the recess.
Not the issue. Water tank breather tube was plugged. No air out, no water in.
All cleaned, tank full, pump operating normally.
Thanks to all.
One addendum....the fill line breather tube has a small screen covering the outside end. Ours is corroded badly. I’m going to try to restore it. But, I’d like to get a replacement.
I’ve looked and I can’t find anybody that supplies these tiny screens.
Suggestions? Make my own??