The trunk of my 2005 Nissan sentra is locked and can't open even with key

Hi, I'm not sure, but check and see if the back seats lay down. That if you can get inside the car of course.

does the key turn the trunk lock?if not theres one issue right there.the other may be that the valet lever on trunk latch assy. may have inadvertantly been engaged if deck lid was slammed closed.the release solenoid will make noise when activated by fob or lever in car but because of valet being engaged cannot release latch.does key unlock glovebox?if not this may also be a valet key cut.contact nissan dealer to cut regular key.ive seen the slamming the deck lid scenario a million times as the valet lever takes hardly any effort to engage.good luck and let me know how you make out.

you have to remove the bottom part of the seat and then un bolt the upper part

Sounds like the lock tumblers are not operating. Maybe from wear, dirt & grime or possible someone tried to break in to your trunk. The easiest way is go to a locksmith and have them pick the lock and repair the tumbler. They can do this so that your ignition key still operates the new lock.

my 97 had the same problem. if the key fits the lock and will turn the lock but the lock wont open the door then your problem lies in the linkage between the door lock cylinder and the locking mechanism.

if the key fits the lock and the lock wont turn at all, this is what happened to me, then your lock is seized. Ive actually seen this on alot of 95-99 sentras it seems to be some sort of design flaw. what I had to do was to replace the lock cylinder and locate a new key. the locks from a dealer are a little pricy so i went around to salvage yards, every nissan sentra from said year range door locks were all seized, I even tried the 200sx as its the same car but a 2 door, same problem. luckily i found out that the 94 nissan altimas have the same door locks so I dismantled the inside door panel of said altima and snagged both front door lock cylinders. i also got lucky as the key was still in the ignition, replaced both locks and got a key for about 20 bucks. depending on your problem you might need new lock cylinders

With many cars you can go through the back seat in order to unlatch the trunk lock with a screw driver, though I believe the Sentra has a rear seat reinforcement panel that has much smaller openings. I read where you wrote you have the "same problem" though we do not have the ability to see what you have seen and made that comment on. If you please, let me know more specifically the initial problem that you identified with.

Regardless, if you cannot open the lock with the key, then the lock tumblers have probably failed. It is quite possible someone may have tried to break in your trunk, ruining the tumblers in the mechanism. You need to replace the trunk latch. It is rather unusual that it would have failed on your car - it is only 9 years old.

Trunk latches have varying degrees of difficulty with regard to installation, though if not mechanically inclined, a repair shop may not charge more than $20.00 to install. This is, however, simply a guess as to how much you would be charged. You would do well to spend some time with your local yellow pages. Price the lock through Nissan, and compare repair shops to Nissan's repair facilities.

Good luck, and thanks for using Fixya

fold down back seat and manually release the latch them inspect lock for trunk

Replace Trunk Lock Cylinder , Opens up With Power Button or Release Lever ? If not the rear Seat comes out Simple and W/ Light You Can Open turnk Through the Rear Seat Opening. Hope this Helps

Sounds like the trunk latch actuator is out.

put some oil in barrel of lock ,if this doesnt work after a day of soaking then go through back seat open boot and lubricate everything in sight and behind the panelling