Circuit/System Description
WARNING: This page is about a different car, the 2011 Chevrolet Cruze. However, it is still accessible from the selected car via links, so may be relevant.
The instrument panel cluster (IPC) illuminates the cruise control engaged indicator based on serial data messages received from the engine control module (BCM) or the powertrain control module (ECM). The indicator is commanded ON when the cruise control system is controlling vehicle speed, and turned OFF with the system disengaged.