If you can not remove fasteners from outside of trunk you must make a cut-out inside of trunk so you can get your hand to access bulbs.
check the bulbs?
If you can not remove fasteners on outside, you may need to cut a section out of the inside of trunk to get your hand by the bulbs.
OPEN THE TRUNK LID. JUST INSIDE THE LID BEHIND THE LICENSE BULB CASE ARE 2 PHILIP HEAD SCREWS THAT REMOVE THE BACKING PLATE. ONCE YOU REMOVE IT YOU CAN REPLACE BOTH LITTLE BULBS. THEN PUT THE PLATE AND SCREWS BACK IN YOUR READY TO GO.....
You may need a new flasher.
I hope you have some sockets and some spare time! You have to pop the truck and actually remove the entire back light panel from the inside (about 9 bolts). Now you can change that teeny little bulb and spend 15 more minutes putting the bolts back on. Viola! Simple, right?
you need to remove the inside panel to get to these bulbs
Remove the door panel.
Sounds like the light bullb\bulbs for you gauger cluster is out. You will have to remove the cluster to get to the back of this to change the lights.
Remove the entire headlight assembly to gain access to the bulbs.
You need to remove the liner on the trunk lid. That will give you access to the license plate lights housing. Remove the sockets by twisting 1/4 turn and replace bulbs. Size for bulbs are 2825
From inside the trunk,twist the socket counterclockwise to remove the socket...
Changing a headlight bulb in a 2007 Buick Lacrosse can be done easily. Just remove the cover piece and change the bulb.