Battery Rundown Protection/Inadvertent Power

WARNING: This page is about a different car, the 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, 2002 Chevrolet Silverado, and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

In the event that any of the interior lamps supplied voltage by the inadvertent power relay and ground from the courtesy lamp relay were to remain on when the ignition is OFF after a period of 20 minutes, the BCM will deactivate the inadvertent power relay turning OFF all of the lamps on that circuit to prevent total battery discharge. Only when the ignition switch is cycled back to the RUN position will the BCM reset the internal timer and reactivate the inadvertent power relay. When the inadvertent power relay is not energized, the BCM utilizes the inadvertent power courtesy lamp supply voltage circuit to monitor for a courtesy lamp switch request signal. If a courtesy lamp switch is activated, the BCM will receive the signal to energize the inadvertent power relay by grounding the control circuit.