License plate lights are they fused?

SOURCE: no back up lights or license plate lights

First chk. all fuses and bulbs. There is a backup light switch under dash either on steering colume or someplace close. plate lights should be hooked in with running lights, If bulbs are ok chk for wire unhooked or bad ground. can't help on diagram.

SOURCE: 2002 CHEVY TRAILBLAZER LICENSE PLATE LIGHTS(2)

there is none, will have to replace lights, should came on with running or parking lights.

SOURCE: License plate lights do not work.

The licence plate lights are in the same line as your tail light wiring assembly. I assume your tail lights are working or you would have got a ticket for that. The wire is either cut, broken or unhooked from the tail light wires (which usually are brown). If you can not find the problem, you can always run a new wire to the tail light wire from your licence plate wire. Then they should work.
Your other problem is that the license plate ground is rusty & not grounding, which would also not let them work, so you should probably check that first. Rick

SOURCE: license plate light doesnt work, need fuse number. charyslerr 300 05'

You need to change the bulb there.

SOURCE: taillights and license plate lights not working

there is a short somewhere.put a test light in place of the fuse.
the light will glow bright.when the short is removed,the light will go dim