I have a 1999 Mitsubishi Galant. I recently replaced the battery and a day after I installed it, the battery was dead. I replaced a couple fuses and was able to get the car started but now my AC/heat, power windos, and headlights will turn on and off with no key in the ignition. I believe this is what is killing my battery. I checked every fuse and they all look good. What could possibly be the problem? What even powers those things?