How do you turn on security beeping on an 1998 Audi A4?

When I lock my car, the security beeping doesn't go off. I called the Audi dealer and they said that there was a way to turn it on and off but they didn't know how... All my doors are closed and the car locks but it doesn't beep. How can I turn the security beeping back on?|||There may be an adaptation value that the dealer will need to change for this to happen, but I have never heard of it. They should already be programmed to do this. There may be a problem with the alarm horn or the car may be thinking that a door is open preventing the alarm from being set. This is all something that a dealer will have to look into.|||are you using the key or the box//try locking the door with the key//lock and unlock with key both sides