Not familiar with your rig, but I will tell you that water sometimes travels a long distance from it's source to the discovery point.
You have a fresh water leak most likely in a wall or hidden in a cabinet. I hope it's fresh water. Is the bathroom nearby? Sometimes the leak will only appear when one faucet is running. Lot's or variables.
You might have the thread moved to the Tiffin forum here listed under owners forums.
Good luck and happy hunting!