Circuit/System Description
WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) controls the Run/Crank relay through the run/crank relay coil control circuit by applying voltage to the circuit. The Run/Crank relay is energized when the ignition switch is in ON or START, or when a remote start is requested.