I don't think the 93's have auto headlights.
Definitely test the battery, if it has a dead cell it could drain internally by itself. Apart from that, you can do a simple fuse pull test. Disconnect the negative battery cable at the battery, then connect a multimeter between the end of the cable and the battery's negative terminal. Turn the multimeter on and set it to amp measurement. If it has a short somewhere, the amp draw will be slightly more than zero. Get into your fuse panel, then pull one fuse at a time. When the fuse you pull makes the multimeter read zero, you have found your power drain. Then you can start taking a look at everything in that circuit instead of not having a place to start.