Open the trunk and pull the carpet away from where the back of the lamp is. You may need to remove clips that hold a cargo net so that damage does not occur to the carpet when pulling it away. Once the carpet is pulled back you will see three or four studs going through the body sheet metal that has nuts on them. These need to be removed in order to remove lamp housing. You may have some sort of other retainers holding the lamp on instead of nuts. Once the retainers are removed pull the lamp off and remove the proper socket from housing and replace bulb.