While car is off. The exterior lights blink on and off. Kills battery. Why?

Hello, I think you have a bad or un-adjusted door switch, hood switch, or trunk switch. I'm referring to the switches that tell the PCM and body control module that the door, hood, or trunk is open. That would explain why the headlights flash when you leave them on AUTO, and why the interior lights flash when you drive sometimes. It could also be a bad connection at one of the door switches, or a combination of multiple issues. My gut says check all the door switches. Another strong possibility is that the ignition switch (electrical portion) may be bad. This would also let the lights come on when the lights are turned to AUTO. Now, here's the kicker, the headlight switch/dimmer switch could also cause these issues, because it receives power when the vehicle is off. If it is shorting internally and intermittently... your symptoms are replicated exactly...