The rain collects into the gutter and is supposed to dump to the quarter window section. When it dumps under the window, it should drain into the rockers from a small 1/8" hole in the channel area. You might find that the hole is plugged with grease or dirt? Mine was on one side when I took my car apart. Once in drains into the rockers, there is a drain opening (a square hole in the rear of the rocker area) that the water drains to the outside. You may have a rubber flapper covering the hole, but mine were missing and the opening half blocked with the floor from the factory.