My trunk lock cylinder was seriously crapped up. I pulled it and cleaned the heck out of it. One of the tumblers still won't slide smoothly so it still doesn't work, but I fixed my keyless remote for the trunk so I stopped caring.
Before you go through the hassle of replacing the locks, pull each one out, one at a time, and try cleaning them thoroughly and lubing them with graphite lock lube. It may do the trick.
Scott
