12V battery draining by ~100mA to the AMD pin of the Converter...

wow....

I'm not very familiar with the Gen 1s, but isn't there normally a small drain on all batteries when the car is off? 100mA doesn't really sound like a lot.

 

100mA would take almost 3 weeks to drain a suitable [pack] of AA batteries. That's a very low draw, unless your 12v battery is pretty lame.

 

How long did you test for? If it was less than a minute, you might try waiting longer and seeing if the draw goes down.

I have tested the current draw from the aux battery before, and when I first hook up the meter, it shows maybe 1 A for a few seconds. It then steps down to something around 0.1 A for maybe 30 to 60 seconds. After that, it drops off to a lower value, around 0.05 A or less (from memory).

If you've got the trunk open to test this, don't forget to disable the trunk light. I find it's easiest to unclip the whole light fixture from the ceiling of the trunk and unplug the electrical connector, rather than trying to remove the lamp.