Y a un paramêtrage pour ça :
Modern Ford Mustang models are equipped with a seat belt warning light and alarm, often referred to by owners as a "seat belt buzzer." This system is not intended to be an annoyance, but rather, a simple reminder. Ford allows you to program this system, officially known as "Belt Minder," on or off, depending on your preferences. The process is slightly different between the eighth and ninth-generation Mustang (1999 to 2004 and 2005 to 2010)
2005 to 2010 Mustang
1 Turn the ignition to "On." Wait for the seat belt light to turn off, and then connect and disconnect the seat belt nine times (ending with it disconnected).
2 Wait for the air bag light to turn on, then off.
3 Connect and disconnect the seat belt one time. The system will be disabled.
You can repeat the process to reverse the procedure. Source