Lock and unlock buttons for doors work fine but one to open trunk remotely does nothing. Can anyone help?

Try the simpler things first. Check/change the fuse for the remote trunk release. If that doesn't work, change the battery in the remore; it might be weak enough that it doesn't work the trunk. Check your owner's manual. I think there is a way to disable the remote use on the trunk. That might have occured somehow. If so, reset the remote following the instructions in the manual. If none of these work, I'm afraid you'll have to bring the car to a dealer who can check out the receiver for the remote trunk release. Good luck and let us know what you find. Hy