Steve, haven't read back thru all the posts so this may have been covered. Is your W/D closet in the Bedroom/main closet area? If so, is it possible one of the lines is leaking? On my LM this would be near the pinbox area.
Steve,
It sounds like by now you are pretty familiar with the roof... Have you tried to isolate the problem area using a garden hose and only wetting down a small section of the roof at a time? While I don't have a Heartland (yet) I had a problem on SOB and was able to locate it that way.
HTH, Keith
Have you considered that it could be condensation collecting on the inside of the front cap, collecting, and running down till it finds a way out??
Steve, try taking the pinbox cover off and see if anything changes. It's a long shot, but I suppose if the wind were blowing enough while it was raining, some water could be pushed up the cover and infiltrate the area above the pinbox.
A few years ago I had water wick up under a house window flashing that wasn't sealed good and cause damage. The water was actually wicking UPHILL at about a 30 degree angle! The angle of that particular roofline was certainly a contributing factor there and I suppose that could occur here. Instead of the duct tape, try silicone sealing along that entire seam. Again - this is just another shot in the dark with a pinch of scientific support.
Is there any way you could temporarily seal up the cap bottom access holes enough to use a fan and maybe large flexible duct to lightly pressurize the inside of the cap? You then spray bubble solution on the outside looking for bubbles, which tells you that is where the leak is. This is what RV professionals do searching for leaks on the main body of the trailer. Good luck!!!
Just a comment on sealing the front compartment gaps. If you wedge a U-shaped section of screen material along the gap between the vertical frame and wall, and then fill it with expanding foam, it helps seal those gaps.
Steve, You probably should have bought stock in the sealant company before starting on this adventure. Hope the fix workis! Please let us know.
I am glad it worked for you. I am just waiting for it to dry up a little here and I will be doing the same thing. I am also going to get some new plastic insert and up it in with a screw right at the intersecting point.
Steve