Circuit Description
WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Ignition switch supplies ignition voltage to Sensing and Diagnostic Module (SDM) connector terminal A1 via SIR fuse, located in underhood fuse block, above left wheel well. When ignition is turned on, SDM responds by performing tests on SIR system while Instrument Panel Cluster (IPC) flashes AIR BAG warning light 7 times. If system is okay, AIR BAG warning light will turn off.