Side Impact Sensor (Sis)
WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
SIS is not part of side impact air bag module deployment loop. SIS provides input to SDM regarding severity of side collision.