Some components only draw current when they are "booting -up". After that, they drop down to lower current. The amp meter restricts the amount of current flowing in the test circuit, so it's possible that some device is stuck trying to boot up over and over. Some components draw current all the time, like the remote door locks, theft alarm, clock, and radio. So, some key off current draw is to be expected. In my experience, internal resistance in the battery is usually the cause of a battery going dead while sitting, even over night. (self discharge) It may be difficult to grasp, but Lead acid battries have internal leakage currents, especially as they age. Batteries have a complicated "science" of their own. A battery can show good terminal voltage, but not hold a charge. Just thought of something else.... The capacitors for the air bags have a charging curve too.

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Resistance is Futile.