The alarm works by using a remote or the key. It looks like the alarm arms itself when you turn the vehicle off and remove the key from the ignition. The doors must be locked(power), and the lights off. Once 15 seconds has passed and no door or rear liftgate has been opened, then the alarm is set.
When you want to turn the alarm off to enter the vehicle you either use the remote to shut it off or put the key in the door.
To keep the alarm from arming you must lock the doors manually.
If you find that your alarm is going off, you may want to have it checked out. Sometimes the sensativity level needs to be adjusted.
〉 Answered on Jun 9th, 2007 by Lori Johnson, Owner and Instructor at Ladies Start Your Engines