Circuit/System Description
WARNING: This page is about a different car, the 2011 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
When the keyless entry control module receives a request from the keyless entry transmitter to unlock the doors, the keyless entry control module will send a serial data message to the BCM, the BCM will then command the left and right turn signal repeater lamps to illuminate.