From inside the trunk, pull back the gray felt in the upper back corners. There are two nuts on bolts that hold the entire unit in. Take these nuts off, and the light assembly can be pulled out of its socket from the outside. Then you have access to the bulbs from the back side of the unit. Hope this helps. It is very easy to do.
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My 04 has a stiff plastic liner in that area that is held in with the plastic nuts on what appear to be long bolts (2) used to hold the trunk net in place....I will try to get around it to the felt and find the 3 nuts that hold the light fixture in place...
The plastic liner is held in with the plastic nuts that are actually on the end of the tail light assembly bolts. Once you get the liner off and the upholstery, just remove the nuts from the bolts and you've got it!