Well, I'm not sure what type of trailer you have, or where the water leak appears. Leaks, as stated, are very deceiving. An example is on the 3400Rl that I had. DW found water in the cabinet between the stove and refrigerator. First thoughts are that the refrigerator was leaking, but that was far from what happened.
on the outside, where the refrigerator vent is, the big square thing with the two plastic thumb locks, the manufacturer dogged the frame down with wood screws. When tightening the screws on the bottom of the frame, it drew the frame down and slanted it in. Any water coming down around the frame would seep to the back instead of coming out down the side of the trailer. Pulling the screws out, they were rusty indicating water seepage.
The fix was to buy 1/2 inch aluminum angle iron at the hardware store, cut it to the length of the bottom of the frame, insert it under the frame, silicone the wood screws and reinsert, and silicone along the lip of the frame and the angle iron, along with a silicone dam at each end.
Never had another leak in that area.
Good luck in finding the leak.
Wayne MSGT USMC (Ret) & Earlene (CinCHouse)
2008 Winnebago Destination 39W
It is what it is, and then it is what you make of it.