The trunk latch on my 2005 350Z sticks sometimes and does not fully unlatch. I use the remote and after about five times it will open properly. I tried spraying WD-40 on the latch and it did not help. Rodney

There are a few items that could cause this concern. First, the trunk latch actuator could be getting weak. When this happens, the actuator tries to unlatch the trunk lid but just doesn't have the necessary strength to do so. In this case, the trunk latch would likely need to be replaced as most actuators are integrated into the trunk latch assembly. Second, there could be a wiring issue for the trunk latch actuator. A poor power or ground circuit that has high resistance could still allow the actuator to try to actuate but would have insufficient voltage to do so. Circuit checks with a digital multimeter would be necessary to identify and locate this issue in the wiring. Lastly, it could be a latch linkage issue. Sometimes a pivot point or other crucial linkage for the latch can break which disconnects the actuator from the latch release lever; this results in the sound of the actuator working properly, but because it's not properly connected, the latch is not released. To resolve this issue, most of the time latch replacement is necessary as the individual components of the latch assembly are rarely serviceable (sold separately). You can read more about the symptoms of a failing trunk lock actuator here: https://www.yourmechanic.com/article/symptoms-of-a-bad-or-failing-trunk-lock-actuator

Before taking this problem to the dealer, you might check this quick fix. I had the same problem on my 2007 Pontiac G6 Gt Convertible, and just resolved it.
First, you can access your trunk by disconnecting, and then reconnecting your negative battery terminal-this clears the safety code momentarily allowing the trunk to be opened using your trunk release button.
After you have the trunk open, check the wiring harness located in the top right corner of the trunk lid where the hinge is attached to the trunk lid. My wiring harness had come loose, allowing a wire to get stuck in the hinge, resulting in a cut wire-it was a red one. I spliced the wire back together, taped it up with electrical tape, and then secured the harness to the hinge assembly so wires couldn't come loose again. The problem resolved immediately with no further issues. Good luck.

check that latch is releasing when using remote. remote uses a cable to pull latch and cable may need to be lubed causing the latch to stick open. Let me guess if you slam a couple times it will latch, lube the actuator cable and latch well. hope this helps

adjust the latch so that the catch will lock over properly. You may need to use a round bar ( screwdriver blade ) Place it under the latch and while pressing on the release button pull the latch out to the open position. The latch may be 1/2 closed before the boot is put down and the latch will not go any further

Then you probably have a sticking trunk latch, a weak/partially shorted trunk latch actuator, or high resistance in the trunk latch actuator circuit.

A problem I had with my 2003 BMW was that the wiring near the trunk hinge that feeds the lock mechanism had been bent back and forth enough times (I open my trunk several times a day) that some of the wires broke. The only way I could get in the trunk was by the mechanical key. The fob and the button release in the cabin did not work. I was able to access enough wiring before and after the hinge area to do a continuity check on the wires and at least a quarter of them had broken. Later I realized that the third center brake light (which is on the trunk lid) was out too. After some patience of unraveling all the wiring I was able to reconnect everything ... but it took several hours....
In your case I do not understand that your latch will not open. Usually if it is set in the lock position when open ... you can stick a screw driver in the mechanism and rotate back the engaging hook which then stays in the open position until you close the trunk again.
If that is not the case with yours, then the mechanism may indeed be toast.
Helpful?

I did this to my car once. Be sure the latch isn't closed as you are trying to close the trunk. With the trunk open pop the trunk once, then see if the trunk latches properly.

most likely cause is latch cover plastic has broken and got lodged in the latch mechanism. now the fun part, fold down back seat , slide into trunk with a phillips screwdriver a flashlight and a large strait blade screwdriver, once in trunk remove trunk cover, then with strait blade unlatch the trunk. once lid is open remove latch and take out broken plastic to free up latch and reinstall then retest before closing trunk.

sometimes they will have a pull handle on them. why cant you just grab the keys when you crawl theu the seat?