Mystery Component

Here are Barracuda drawings but basically the same. If you leave your headlights on and ignition is off when you open a door you get the buzzing. Assuming the buzzer still functions. This was installed on all A01 optioned cars.

You can see you have dual contact door switches. One set of contacts operates the map/dome and the other the headlight warning buzzer arrangement.

Those are the set I created and look at the lower left side for the Buzzer wiring and trace it from there. There is a connector off the headlamp switch (Black wire) that ties in as well as either door switch (yellow/black trace) and the black white is fused power from the fuse box.
Those are the set I created and look at the lower left side for the Buzzer wiring and trace it from there. There is a connector off the headlamp switch (Black wire) that ties in as well as either door switch (yellow/black trace) and the black white is fused power from the fuse box.

1969383S Where did you get the pdf of the wiring diagram you shared?