Circuit/System Description
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) monitors the cruise control indicator switch. When the cruise on/off switch is pressed ON, the cruise control switch is closed and the signal circuit is low. When the cruise on/off switch is pressed OFF, the cruise control switch is open and the signal circuit is high.