Cadillac XLR Forum Discussion, Dead battery and key won't open trunk in Past Cadillac Vehicle Discussion; key turn's from the 12 o'clock position to 3 o'clock position
can not get trunk to release never checked from ...
Had the same problem. It helps to have two people open the trunk, but you can do it yourself. The owner's manual doesn't do a very good job of explaing how to open the trunk with the key other than, "Use the key to open the trunk."
After the key is rotated, immediately (we're talking milliseconds here) lift the trunk by pressing upward on the rear center brakelight or under the license plate area (by the decklid open switch) in one fluid motion. It takes a little effort, but it will raise. Don't grasp the rear decklid from the bottom; the auto cinch mechanism will release and then pull the decklid back, trapping your fingers.
For your battery: The XLR always draws power. If left parked for extended periods (>three weeks) you will likely experience a dead battery. Always keep it connected to a Battery Tender or Battery Minder when the car is stored, they not only keep it charged, but prevent the battery from sulphating, which ruins the plates. When batteries are discharged and remain idle, they begin to sulphate, which limits how much of a charge they can take and how long they can hold it. These are great products, and a must-have for every XLR owner who stores their car in the winter.
To gain access into the car, you can create a looped tool, and pass it through the window glass seal to hook around the door release lever. Failing that, you'll have to have your car towed to the dealer and let them open it.