Circuit/System Description (C99)
WARNING: This page is about a different car, the 2017 GMC Acadia. However, it is still accessible from the selected car via links, so may be relevant.
When the ignition switch is turned to ON, the inflatable restraint sensing and diagnostic module (SDM) continuously checks the air bag enable/disable switch position switch and circuit defect by letting regular voltage flow through the switch circuit and verifying the current. The passenger air bag switch controls when the air bag is enabled or disabled and notifies the driver when the passenger instrument panel air bag is enabled or disabled using the passenger air bag ON/OFF indicators. When the inflatable restraint sensing and diagnostic module receives the signal from the passenger air bag disable switch (on/off), the inflatable restraint sensing and diagnostic module will then provide voltage to the appropriate indicator.