You Guys may or may not know that its quite common for rain/water to leak in via the High mount Centre Stop light on late model Crafters. If like mine, the holes under the mounting screws are covered as part of an internal build, the water wont easily be seen, thus it trickles down into chassis. Not Great.

The simple fix has been, remove, clean all surfaces, apply silicone to sealing surfaces, refit.
No more leaks.

Steve.