Replacing a Bulb is quite easy given the brilliant design. The entire Bulb Assembly just snaps out (and then unplugs). If you're wanting to replace the Inner Light Fixture that is in the Trunk Deck, you will need to remove most of the Push Pins in the Trunk Liner and move it away. There is one retaining mechanism that then holds the Inner Light in place. You have to work the Light out of the Trunk Deck but it's not that hard. I just did this yesterday to reseal my Inner Trunk Deck Light.How to replace the brake light on a 2004 325 ci?