[RUSSELL]

Do you have a gas detector on your AS if so it will drain down the batt. Also the engine computor is in stand by and will use some power.
Suggestion disconect the positive on the battery and put a meter between the battery post and the batt cable if you have any voltage reading start pulling fuses one at a time until it voltage reading goes away.
This will tell you what is on.
Regards from Russell sunny and cool Tucson Az.