Whenever I wash my car, I get water in the trunk. I determined that the water was coming in through the tailights. I replaced the tailight gasket which reduced the leak, but it's still there. Any suggestions how to eliminate the leak? I'm considering putting silicon on the gasket, but I would rather not if I don't have to.

what kind of gaskets? There are thin plastic ones that are junk and there are thick foam ones that are better.

The tailight gaskets that I got were thick rubber gaskets. They looked like the same style as what I removed, except that the old ones were dry and hard.

There are 3 places the boot leaks
1/corrosion under the back window glass...and when trying to find this one, the water can be hidden behind struts/hinges making the route very difficult to find
2/the seam on each side by the hinges, under near where the seal rubber sits
3/And the tail lights...
Silconing can fix...I found the best way was to stick the gasket to the tail light with a couple small spots.. The put vasaline or smear of grease on the body where the gasket sits....a good layer of silicone on the gasket then put in place
Do not do the screws completly up...a couple mm short
Then when the silcone has gone off, tighten up and alighen the lights
The grease/vasilone on the body stops any major sticking of the silcone to the body, and major hassle further down the line
No torguing fully till slicone is cured, lets the gasket form, then gives a little more compression for better seal.

Thanks, I like your suggestion of grease on the body to prevent the silicone from sticking too much.

This same principle can be used to make gaskets for a 10 bolt, heater box, carbs and inlets, to sealing up windows and doors in your home and even making a new seal for the ktichen oven .....

I use butyl. The same stuff made to set windshields. It stretches to any thickness, sticks very well, and can be removed with mineral spirits. Silicone on the body is a bad idea in my experience.