12 ma won't pull a good battery down to 9 V in 4 days. Use a clamp on amp meter and probe around. Check the alternator to battery wire for current flow, you might have a positive diode starting to fail. I chased a similar problem on my Ranger of interment battery drain, changing the alt fixed it ( changing the regulator didn't )

Also, I've had electrolytic capacitors leak causing electronic circuits to turn on.