Quote Originally Posted by psychos2
something to check may be the anti theft unit. when the alarm goes off the horn and lights both come on. if there is something wrong with the unit it may cause this. shawn
I also considered that at first, but the only things initiated by the alarm system upon an unauthorized entry are the interior lights, the exterior lights (except the headlights), and the horns. The starter is also disabled.

The manual also says that the anti-theft system enables the anti-theft buzzer (although my VX seems to have more of a beeper) for the following situations: to signal that the system has been armed, the system has been disarmed, during system programming, and when a door has been left open. No mention of the headlights there either.