How do I replace the rear tail light in a 2007 Buick Lacross

Hello, If there is no cutout area in the trim directly behind the rear light housing inside the trunk, the carpet or trim will need to be moved to access the rear tail light socket. You can gauge which light it is by observing the position of the lights that work on the outside of the light and compare those positions to the installed positions inside the trunk. Twist the bulb socket to the left or right about a 1/4 turn, and the light bulb will come off with the socket.