Lights Flash at Unlock
WARNING: This page is about a different car, the 2003 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
This feature turns on the exterior lamps when the remote keyless entry transmitter is used to unlock the vehicle. The lamps will remain on for approximately 20 seconds unless a door is opened, the ignition is turned to ACCESSORY, ON or START or the remote keyless entry transmitter is used to lock the vehicle.