2003 Corolla S

You need to do a parasitic draw test on it.
To do this you need to connect a AMP meter or muti-meter inline with the negative battery cable and to the negative battery post.
After disconnecting the battery cable open the door and turn on the head lights for a sec to make sure all the power is drained down, then turn everything
in the car off and close all the doors, also if this has a under hood light remove the bulb. you Should not see any more then 50ma on your meter, if you
see more then that start removing fueses one at a time until the draw goes away, that will tell you what circuit has the problem.
Good luck and keep us posted.