Leaky MKIII Tails

I have a 95 jetta that leaks through the left taillight. It keeps blowing my brake light, when it gets wet. Is there a way to find and fix the leak in the housing?

I take it the water is getting into the light itself, not leaking into the trunk area. If the lens is not physically cracked then it leaks in where the lens section attaches to the rest of the housing, it's glued together. You can try resealing with siicone glue around the seam.