I have an electrical problem where the battery.

I have an electrical problem where the battery keeps draining to zero. The only way I can keep the battery charged is by pulling a plastic yellow plug half way out on the drivers side and then when I want to use the car then push it back in to engage the dashboard lights. I have tried googling the issue and see that many people in the past have had this issue, but no one has ever posted a solution. I hear that it might be related to a fuse or short in the driver's side electric window or drivers side electric door-locks, but I do not know how to determine for sure.

Is there anything I can do? For example will a diagnostic tool such as a OBD-II device help me figure out the electrical problem?