2003 Nissan Altima has a slow drain
2 Answers
Make sure the missing trunk latch is not keeping the trunk light in an energized position. If that is not the cause then you will need to isolate the drain by pulling fuses one-buy-one to identify the circuit that causing the drain and fix it.
Since the trunk latch is missing. I would start there to look at as the source of the electrical drain. If that checks out OK, then you will need to go trouble shooting by pulling fuses until you find the one that is powering an otherwise dead circuit. Do this by hooking up a voltmeter in series with the battery with the car off. When a circuit is found that is powered with the car off and it goes dead when the fuse is pulled, that will tell you where to start testing individual components powered by that circuit. Check both the power and ground sides when evaluating.