2000 Nissan Altima trunk latch (self) activates (opens) when ingnition is turned to off.

SOURCE: 2005 NISSAN ALTIMA 2.5S THE TRUNK RELEASE BUTTON

check in your glove box on left hand side.valet switch may have accidentally set.let me know how you make out!

SOURCE: changing headlamp for 2000 nissan altima

I just replaced the driver's side headlamp on my 2000 nissan altima. The manual advises you to take it to a dealer or details a long process which involves removing the bumper protector -- none of this is necessary. I am not mechanically inclined and a coworker and I did it on a lunch break. Here's how:
1) Disconnect the battery by loosening the nuts that attach both the positive & negative contacts.
2) Once loose, slide off the contacts. At the base of the battery (closest to front of the car) there will be another nut that you'll need to remove (this loosens a clip which holds the battery in place)
3) Once loosened, lift out the battery which will enable you to see the headlamp connection.
4) There is a white plastic ring that attaches to the headlamp connection. Twist this to the left (about a quarter turn).
5) Once you have loosened the white ring, you should be able to gently pull out the headlamp assembly.
6) Remove the headlamp from the socket by pushing on the plastic arm which will release the lamp from the socket (sounds confusing, but once you have the piece in your hand it will make sense)
7) Insert the new lamp into the socket & slide assembly back into the hole. Note. There is a groove in the assembly which will align with a notch in the headlamp frame...you can see this by looking through from the front of the headlight cover on the outside of the car.
8) Replace the white ring and twist to the right to secure in place.
9) Replace the battery & bolt you remove.
10) Replace the positive & negative connectors (hint: don't forget to replace the plastic battery cover before you attach the connectors).

Hope this helps...let me know how you make out.

SOURCE: My trunk won't open.

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

SOURCE: can not open trunk

There is a "cancel" button inside the trunk that makes the trunk lever release inoperable. In this mode you can only use the key to open the trunk. Open the trunk with the key, look around the locking mechanism and slide the button.

SOURCE: 2005 Nissan Altima electronic trunk latch does not

sounds like a bad connection on relay start there first do ya hear a click at all. if not check fuses. otherwise wiring would be where I would start