Circuit Description
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The ignition switch closes, the signal circuit is low, when the key is in the ignition, and opens, the signal circuit is high, when the key is not in the ignition. The body control module (BCM) monitors the key in ignition signal circuit in order to activate an audible warning.