Beeping while driver side door open

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I have a 2009 Yaris two-door hatchback. The car beeps when the driver side door is open whether there is a key in the ignition or not or if the headlights are on or not. If the key is turned to the on position or running the beeping will stop after moment even with the door open.

There was some work done by the previous owner related to the power outlet. Found a wire running from the back of the power outlet plugged into a fuse socket on the Type A panel under the dash with a 30 fuse in-line. Unplugging this wire only removes power from the power outlet (obviously). My thinking is there may be another wire behind the power outlet it was originally plugged into and if I were to remove the lower dash I will see this.

Any thoughts? Guides on removing the lower dash or something to access the back of the power outlet? I've searched here and general Googling to no avail as of yet.

Thank you all in advance for any help.