[robmon]

On my 1999 SL500 I get a high pitch intermittent tone after remote locking and then remote unlocking the car. The tone has random time on and time off about 3 sec. This will continue until you hit the panic button (red) on the remote. When activated the alarm works properly. The tone is coming from alarm horn area.
Any Suggestions

 

[bobterry99]

In my opinion it isn't unlikely that the alarm siren is faulty. To prove this you would check to see if it is producing an output in the absence of a signal from the alarm module to which it is connected. The siren is located inside the fender in the general area of the fender decorative vent.