Do it yourself, remove and change the tail light assembly on your GMC Acadia made between the years 2007 and 2012. You can make this simple replacement in about 15 minutes, using a small flat blade screwdriver and a 7 mm socket wrench.
First, you have to open the tail gate and locate two small plastic covers (marked with red circles in the next image) next to the tail light assembly you wish to replace.
Pry out carefully these plastic pieces using a small flat blade screwdriver. This will uncover two 7 mm bolts, that actually hold the tail light assembly attached to the body of the car. You can remove them very easily with a socket wrench and an extension. After you finish this task, you can remove the tail light by pulling it out, straight towards you. The assembly should come out without much effort. You will now notice an electrical harness (as you can see in the picture below), that power the housing. Unplug it, with the help of the screwdriver if needed, and that’s it.
At this time you can install the replacement. So, reconnect the electrical harness, make sure you align properly the new tail light (watch for the two pins on the back) and snap it back into place. Secure the piece with the two bolts and you are done. This is all you need to know, if you have to change by yourself the tail light assembly on GMC Acadia, manufactured between the years 2007 and 2012.