How to change a tail light on a 2000 nissan frontier

Take the bulbs out and check them, replace any that look black or if the filaments don't look good

it should be in the fuse boss bar in the engine bay

CHECK INSIDE THE TRUCK QUARTER PANEL FROM INSIDE THE TRUCK BED AT BACK OF THE LIGHT COVERS. MY IS A 2000 FRONTIER AND I HAD TO REMOVE BEDLINER TO GET TO THE SCREWS. NOT A VERY BIG OPENING ON THE BACK OF THE LIGHTS.

Sounds like multi-function/ turn signal switch

The entire bed line will need to be removed. The long screws that hold the metal bracet where the bed extender attaches also hold the tail light assembly in place.
I pulled the bed liner up at a 45 degree angle and layed it on top of the cab. This revealed the screws. Take both screws out and lay to the side along with the metal bracket for the bed extender.
Now firmly grab the edges of the tail light assembly and pull...there are 2 hard rubber nipples that snap in to hold the assembly. You will feel like you might break it but you won't..just pull straight back hard. The assembly will "POP" out and then you can just twist the back of each bulb there are (3) and pull out..now you will see the bulbs..just pull the bad bulb straight out and push the new one into place. Now just reassemble. Total time will be 30-45 min. for this repair.

Lower tailgate. should be screws to remove lens assy.

look for screw inside the bed area, adjacent to the tailight covers. Remove two screws, and the taillight assembly pulls out

Does the fuse have power in and out when a test light is used? This test would be run with the light switch on.

Check the switch that brightens and dims the dash lights

do you have a bed liner?? if so, you need to move the bed liner away from the rear lights in back to access the screws that hold the tail light in. on the side of the bed right by the tail light are 2 screws holding the light in. remove screws, remove tail light replace bulbs, re-assemble.