If the leakers are on the top row, it is the seal between the colored plastic lens and the tail light body. The water runoff from the top and down the rear window goes into the seam between the fender and the trunk lid and runs right down that channel and splats into the upper three lenses right at their seal point.

You might avoid drilling the usual drain holes by sealing up the lenses. Only the clear reverse light is supposed to come off. If the others come off, well - there's your problem. If the others don't, forcing them will likely break them.

With the tail light off the car, clean the sealing area as best you can, and run a bead of good marine silicone seal between the body and the edge of the lens. If time allows, do it in two passes to be sure you get a good seal. It shouldn't be necessary to seal all around the far end of the outer lenses.

In my pre-BBRD days, I was disgusted after find that, having the same problem as you, removing the tail light and gasket, and sealing the gasket to the tail light and to the car body, and still getting leaks into the trunk.

Good Luck,

Bob

:>)

A bead of thinly applied silicone caulk(clear) will take care of any leaking lens gaskets and keep the trunk dry.

If there is "moisture" as in "standing water," the seal has broken and is letting rain, etc., in. I had the same situation in one of my tail lights. To solve the problem, I went to the back side of the light (i.e. the truck side where you change the bulbs), and drilled a small weep hole though the lens so the water could escape. I used a 1/8" bit and had the hole exit beneath the brake light and above the signal light, so it does not show (of course where you need the hole depends on where your leak is -- duh . . .). Anyway, that solved the problem for me, without my spending a mint on a new tail light assembly. Just be careful when you drill to avoid cracking the lens.