Circuit/System Description
WARNING: This page is about a different car, the 2015 GMC Acadia, 2015 Chevrolet Traverse, and 2015 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
The instrument cluster illuminates the cruise control engaged indicator based on serial data messages received from the engine control module (ECM). The indicator is commanded ON when the cruise control system is controlling vehicle speed, and turned OFF with the system disengaged.