I did this Mod on 10.15.07
A hole in the bottom of the jeep will shoot mud (where the piece of foam is)up and behind both of the rear tail lights.
First remove the tail lights The 2 screws only on the right side of the left light and the left side of the right light. Then clean out the cavity well! Remove the foam block from both holes.
Left side out.
Right side out.
Next you see the hole on each side.
Left side hole.
Right rear hole.
Then place a piece of rubber over the holes.
Next fill with Marine low expansion foam.
Left side full up to the tag wires and don't get any on the gas breather.
Right side about half way up.
Let cure, reconnect wires to lights and screw back in..
Left rear done!
Right rear done!
Now no more mud or stuff will go up into the holes and rot out behind your tail lights..
I got the marine low expansion foam from a boat repair house. It is made to breath and will not let water stay in but keep dirt out!
On the 23rd at 7am I removed the right tail light and put in 28oz of water on top of the foam then put the tail light back in.
Just a little bit ago (3pm/1500hrs) I removed the right tail light and checked the cavity and not a drop of moister was found! So this was a great fix it keeps the dirt, & mud out but still lets it breath!
As of today still works great!