Circuit/System Description

The body control module (BCM) controls the ignition main and the retained accessory power relays by applying voltage to their individual relay control circuits. The ignition main relay is energized when the ignition is in the ON or the CRANK position. The BCM controls the ignition main relay through the control circuit by applying voltage to the ignition run/crank relay control circuit. The retained accessory power relay is energized during all power modes, except OFF-awake and CRANK. The retained accessory power relay is also energized for approximately 10 min after shutting the ignition OFF, providing no door is opened. The BCM controls the retained accessory power relay through the control circuit by applying voltage to the accessory/retained accessory power relay control circuit.

The BCM also controls the battery saver relay through individual circuits by applying voltage to the battery saver set and reset circuits. The battery saver relay is a latching relay that when enabled disconnect some modules from their ignition power or memory power sources.

The engine control module (ECM) controls the powertrain relay by applying voltage to the powertrain relay control circuit.