Crown Vic sending me morse code

On a rare occasion my 2003 Police Intercepter will make sounds like very slow morse code, a speed of about 1 word per minute. It sends me 5 sets of 5 dashes. These sounds are not coming from the radio! What could this be?

Is this at speed?
- Some Crown Victorias were equipped with a speed warning chime.
Does your airbag light illuminate when you first turn the key?
- There is a secondary alarm for when that bulb is out, it's located in the LCM under the dash.

The sounds occur at lower speeds. Maybe 15-45 MPH. The airbag light is constantly lit while the engine is running. I have not investigated the issue with the airbags.