Normal Operation
WARNING: This page is about a different car, the 2006 Mercury Milan, 2006 Lincoln Zephyr, and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
When the brake pedal is applied, the smart junction box (SJB) sends a message to the powertrain control module (PCM) to deactivate the speed control if engaged.
The speed control deactivator switch interrupts circuit CES09 (VT/OG) removing the voltage signal to the PCM when the brake pedal is applied. This is a redundant signal to the PCM.