Originally Posted by L27Buick
could it be his key i got mine dirty and security light came on.
VATS is the resistor-chip-in-the-key system that we're talking about here; however it uses the same Security light on the dash as the factory security system does when locking the car. So what the Security light means depends on when and where you see it light up:
Solid light when attempting to start the car: Wrong resistance of ignition key chip, or a bad connection through the key; car won't start until VATS alert times out in 3 minutes.
Solid light comes on _while_ driving the car: Circuit through the key has been lost for a full uninterrupted 60 seconds. (Car will not shut itself down.) Probably a dirty key or dirty contacts in the ignition key cylinder.
Blinking light while car is off, door open: Reminder only, telling you to lock the car, which will activate its Security system 20 seconds after the door closes. Triggering the security system after that will cause horn honking and light flashing until the correct key is used to start the car (possibly also using the key in the door lock will get it to shut up; I don't remember).