Circuit/System Description
WARNING: This page is about a different car, the 2007 Suzuki XL7. However, it is still accessible from the selected car via links, so may be relevant.
The body control module (BCM) monitors the park brake switch via the park brake switch signal circuit. With the park brake applied, the switch is closed and the signal circuit is grounded. The BCM will then send a serial data message to the IPC requesting the red brake warning indicator be illuminated.