Over the last year I kept having this problem of batteries dying in my Regal. Not just draining but also going bad and no longer holding a charge. Today I did a few checks for drains or shorts in the electrical system. First I disconnect the neg battery cable and connected a test light in series between the neg cable and terminal, tiny spark but no light, and the bulb is working. Next took out my multimeter, hooked it up the same way as the test light. It indicated there was 12 volts present, but only 17.7 milliamps, so likely just the small drain for the ECM and radio memory. Not enough amps to light the test light. I tried pulling all the fuses one at a time as well as disconnecting the pos lead to the alternator and no change in the readings. Not sure what else it could be?