But I'm trying to visualize how water could be getting in the lens. Looking at it, you'd think that as long as the lens itself was intact, the socket that the bulb goes into would do the sealing. But the socket shouldn't even be exposed to water in the first place. That whole trunk area should remain dry.
Could it be condensation, and not a leak after all?
Your thoughts are exactly mine. I have tried to figure it out before how water would somehow find its way into there, but basically nothing comes to mind besides a faulty lens itself letting water in from in between the cylinder part that goes into the trunk lid to the exposed part of the lens itself, if that makes sense (which is why I tried silicone around there).
I would have to say it's a leak. Its not just a small amount of water, but enough to fill the bottom of the lens, and then reach the LED's I have and cause them to rust, giving a very odd appearance to the color of my license plate when it is lit up lol.
The even more odd thing is that if I remember correctly, they filled with a little bit of water after it had rained but before I even drove the car around (eliminating the possibility that water splashing up from driving was somehow getting up into the lens). This made me think my trunk might be leaking onto the rubber socket and into the lens, but as far as I can tell, it is not, all everywhere inside my trunk is always dry. The rubber sockets are in a somewhat questionable condition, but I don't know if that's the problem, or even where or how to replace them, if I even can.
This is the whole reason why I made this post, to see if anyone has experienced similar problems. One other thing that I'll include, but I dont know if it matters, the holes for the lens screws in the trunk do have a spot where the paint has chipped off the fiberglass, and where the fiberglass does look very thin, but that brings us back to our original thoughts that even with that, water should have no place to enter still.