'91FC3C mostly stock, rebuilt 13B. AT.
If I leave my battery connected, it will drain dead.
When I disconnect the Positive cable and use a voltmeter between the Positive Terminal and the Positive cable, I get a 12V reading. My thought was that something was grounded and shorting things.
I tried unplugging all the fuses one at a time to see where the issue was. The voltmeter never waivered.
Then it got weird.
When I disconnect both cables, and use the voltmeter between the cables, I get a 1V reading that slowly (takes about an hour) drops down to zero.
So, not only is something drawing power, it is storing it too.
I'm still searching for an aftermarket alarm battery installed somewhere that might be the culprit. Not finding anything.
Has anyone else had this issue?
Does anyone have any ideas?
Thanks,
~j

 

Instead of using a voltmeter between the negative terminal and cable, use an AMMETER. There are plenty of capacitive electronic circuits in the car that will store a charge. Once you connect the ammeter, look for a current draw greater than 0.2A. Start pulling fuses like before, and watch the current drop. It won't do that with a voltmeter.

 

As mentioned in the post above, set up your meter as shown in the attached jpg.

Also.......always make sure the key is to OFF and not to ACC when removing the key. Meter has to have the capibility to read current/amps.

 

Like he said. Thats the best way you will find a battery Draw. Also make sure your batteries are clean. Batteries can have what is called Surface Discharge. If you put your Meter on a battery terminal and then to the top of the battery you might be able to read voltage if soo clean your battery.

 

What the above posters said. The voltage setting on the multimeter is very high resistance so it'll take a while for the capacitive circuits to drain out unlike the almost no load condition set by the current setting on the multimeter.