I recently had a parasitic drain that left the car unable to start after a week or so of sitting. Ammeter wasn't working for diagnosing but the siren was dead so ... Got a wiper puller from Amazon,removed the cowl, and found lots of leaves covering the drains which probably entered through a missing wiper grommet that may have been lost when I had a cracked windshield replaced several years ago. There was a little water leakage on the passenger side carpet that I let air out. Also I had replaced the heater resistor about a year ago that possibly failed if it had gotten wet because of the plugged drain. Anyway, pulled the siren connector and no more battery problems. Used black tape to act as a grommet until I do a proper repair.