2003 Trailblazer Mysterious Beeping
 

On start up and shut down there is a loud long beeping. This is not the normal chirping as if you left the key in the ignition with the door open or the chime to put your seatbelt on. It started a couple of days ago with 5 short loud beeps and today it has changed to 5 long loud beeps. No warning lights on instrument panel. It has done the short beeps in the past but stopped after a day or so.