The device is controlled via the DWA horn.
The central locking system in your vehicle is controlled by the comfort control module. Unlike previous models, the central locking system is now electrically operated, with a separate actuator motor in each door (door control module).
The turn signals are controlled in the conventional manner; the corresponding pin assignments for the comfort control unit can be found in the wiring diagrams.
Rainer's link regarding the ZV (central locking) adjustment is a good starting point, but unfortunately, VW made slight modifications during the different model years.
{Comfort control unit}
ECU coding.
Select STG 46 (Comfort Control Unit).
STG Coding -> Function 07.
Central locking (2 power windows):
00256 - Single door opening.
00257 - Complete door opening.
Central locking (2 power windows and memory function):
00258 - Single door opening.
00259 - Complete door opening.
Central locking (for 4 windows).
04096 - Single door opening.
04097 - Complete door opening.
Central locking (for 4 windows and with memory function):
04098 - Single door opening.
04099 - Complete door opening.
ECU adaptation (up to 8.97).
The adaptation is not supported by the control unit.
ECU adjustment (09.97 to 05.9

.
Select STG 46 (Comfort Control Unit).
Adjusting the ECU (Engine Control Unit) -> Function 10.
-> Channel 03 (Auto-Lock)
The vehicle locks at a speed of 15 km/h (0 = off; 1 = on).
-> Channel 04 (Auto-Unlock)
The vehicle locks at a speed of 15 km/h and unlocks when the ignition key is removed (0 = off; 1 = on).
-> Channel 05 (Interior monitoring deactivation).
Activation/deactivation of the interior monitoring system by pressing the central locking button twice (0 = off; 1 = on).
-> Channel 08 (unlock blinking).
The turn signals are activated when unlocking (0 = off; 1 = on).
-> Channel 09 (locking indicator blinking)
The turn signals are activated when the system is locked (0 = off; 1 = on).
-> Channel 10 (Alarm horn)
Country selection for the alarm horn (1 = Rest of the world; 2 = Germany; 3 = Great Britain).
Influences the type, duration, and volume of the alarm sound (while adhering to legal guidelines).
ECU adaptation (from 06/9

.
Select STG 46 (Comfort Control Unit).
Adjusting the ECU (Engine Control Unit) -> Function 10.
-> Channel 03 (Auto-Lock)
The vehicle locks at a speed of 15 km/h (0 = off; 1 = on).
-> Channel 04 (Auto-Unlock)
The vehicle locks at a speed of 15 km/h and unlocks when the ignition key is removed (0 = off; 1 = on).
-> Channel 05 (Interior monitoring deactivation).
Activation/deactivation of the interior monitoring system by pressing the central locking button twice (0 = off; 1 = on).
-> Channel 06 (unlocking horn).
The unlocking is confirmed with a short beep (0 = off; 1 = on).
According to the German legislature, it is not approved.
-> Channel 07 (locking horn).
The locking is confirmed with a short beep (0 = off; 1 = on).
According to the German legislature, it is not approved.
-> Channel 08 (unlock blinking).
The turn signals are activated when unlocking (0 = off; 1 = on).
-> Channel 09 (locking indicator blinking)
The turn signals are activated when the system is locked (0 = off; 1 = on).
-> Channel 10 (Alarm horn)
Country selection for the alarm horn (1 = Rest of the world; 2 = Germany; 3 = Great Britain).
Influences the type, duration, and volume of the alarm tone (taking into account legal guidelines).