NICOclub.com has a nice description on how to remove your tail lamps. Nissanclub.com is another website with very useful information as well. Essentially with simple hand tools it is a 5 minute job to remove the tail light assembly from your 08 Altima.
To replace the front side marker light on a Nissan Altima, first, open the hood and locate the marker light assembly. Remove the screws or clips securing the assembly, then carefully pull it out. Disconnect the old bulb by twisting it counterclockwise, replace it with a new bulb, and reassemble the marker light by reversing the removal steps. Ensure everything is secured properly before closing the hood.
you must pull out the entire breather assembly, then you unscrew the housing. Next, flip the retaining clip and replace the radiator.
fog light not working and radio light went out
If you remove the panels from the interior of the trunk you should find the bolts that hold the taillamp assembly to the body of the car. Simply remove the nuts and this releases the lamp assembly.
http://www.paulstravelpictures.com/Nissan-Altima-Rear-Brake-Light-Bulb-Replacement-Guide/Nissan-Altima-Tail-Light-Bulb-Replacement-Guide-011.html here you can see every step to that question.. I just did it.. and works :) by Paulo Fernando!!
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To replace the tail light assembly on a 2006 Nissan Titan, first, open the tailgate and remove the screws securing the tail light assembly using a socket wrench or screwdriver. Carefully pull the assembly out from the vehicle and disconnect the wiring harness. Replace it with the new assembly by reconnecting the wiring harness and securing it with the screws. Finally, test the new tail light to ensure it functions properly before closing the tailgate.
Remove the tie wrap that holds the wires for the light. Behind them you will find a nut that holds the light in place (2 nuts in total).Once you remove them (size 8mm)you can take the whole light assembly out from outside. Then turn electrical connector remove bulb and replace