Mojo,
Your lights are leaking thru the screws that hold them to the back plate, as well as the gasket. I had the same problem with my '06 CCD. You should replace the gaskets AND add an o-ring to the retaining screw. There is a fix for this; check the Classifieds for a kit that replaces the screws with stainless ones and o-rings.
I have some silicone sheet that makes great gasket material. PM me if you need some. Or, you might check at NAPA.
