Roof Leak

Thanks to everyone for the great suggestions. I hope I found the source of my leak at the driver's side end of the L-shaped metal strip (above the wet carpeting) that I now think must cover a transition from the "rubber roof" to the fiberglass rear cap of the trailer. This strip catches most of the water running down the back half of the trailer roof, before it runs over the back windows, and sends it off to the side, where a small dam is formed by a mound of caulking that extends from the metal piece to a roof rack post. Near the "dam" on the driver's side, I found where caulking along the metal strip has lifted off the roof. My short term solution was to clean the area on and above the metal strip with a stiff brush, blow it off with compressed air, and then spray a can of white Rustoleum Leak Seal along its edge - with extra attention and amount given to the area where I think the leak was coming from. This provides a penetrating, waterproof covering that I hope will stick for the rest of the winter. If the leak continues, I will move on to the suggested pressure test and also try a layer of sealing tape. If this patch does stop the leak over the winter, then I can pull the metal strip off next summer, when all will be dry, and fix it right - including use of sealing tape once the mounds of caulking are removed from the many screws. Thanks again.

JRMunn