Re: moisture in trunck
The problem is usually the taillight gasket. Water gets in around the top of the taillight perimeter from rain or washing the car and can't get out. The water condenses out onto the underside of the trunk lid from engine heat but can't escape the enclosed trunk, so it stays in the trunk and the cycle repeats. Replace the taillight gasket to prevent new moisture from entering, then leave your trunk open and let it dry out very thoroughly over several days in the garage or let it air out in the sun on a very hot day to purge the moisture that is already in there. The problem should then be solved.
As mentioned above, this can also cause moisture to condense inside the taillights themselves.