Cadillac Repair Questions? Ask a Mechanic for Answers ASAP
If the battery is dead after just 4 days, this means there is an electrical draw on the battery from one of the systems. Unfortunately, an electrical draw is time consuming to find, and there is no 1-answer, "it this..." type of answer here. The best way to begin to start checking for an electrical draw is to remove the NEG cable from the battery and install a volt meter or test light in between the battery NEG post and the battery cable terminal. The test light should now be light and/or the volt meter is showing a voltage reading (which is the amount of the draw on the battery while the vehicle is idle). With the test light/volt meter in place, start pulling the fuses one at a time until the light goes off and/or voltage reading drops. Whichever fuse is pulled, this is the system that has the draw. From there, the components in the system will need to be tested and the wiring to those components will need to be inspected for any problems. If you do not have access to a test light or volt meter, the best bet here would be a reputable automotive electrician.