[busterbrown]

Like most front bedroom ultra light models by Keystone, the DC water pump is usually secured to the floor next to the bed on the drivers side. It can be accessed by removing the top wood panel next to the bed. On my Bullet, it's in front of the the "laundry" chute.

Another clue that sometimes help in locating a water pump is to denote where the city water inlet and fresh water fill Re on the outside of the coach. Then move inside and look around in that same area for a cabinet or panel that may be removable. Chances are, the pump is secured behind it.

And as Chip indicated, having a good pair of ears while the pump is running should do the trick.