Plumbing routing

[Steve and Cindy]

Installed a new water pump today. Does the same thing as the old one. Nothing. LOL. When I manually pour water into the inlet it works but then when I reconnect the water line it just sucks air. I suppose there’s a broken connection somewhere but not one inch of the water line from the tank is visible anywhere until it comes up through the floor into the van. Any chance anyone knows where the line runs from the tank to the pump in an ‘88?
By the way, how long should it take for the pump to draw water from the tank after it’s been primed? I let it run over 3 minutes. Maybe it just takes longer?