Circuit/System Description
WARNING: This page is about a different car, the 2008 Cadillac CTS. 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 signal circuit and the brake fluid level sensor signal circuit, and sends the switch information to the IPC via the serial data bus. The instrument panel cluster (IPC) monitors the serial data bus, and illuminates the brake warning indicator if it is requested.