Networked Controlled Dimmable Illumination
WARNING: This page is about a different car, the 2009 Mercury Milan, 2009 Lincoln MKZ, and 2009 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
The SJB sends a message over the medium speed controller area network (MS-CAN) to the heating ventilation air conditioning (HVAC) module - electronic automatic temperature control (EATC), the audio control module (ACM), and the instrument cluster (IC) to indicate the back lighting intensity level. When any module does not receive the illumination signal, it defaults to full nighttime brightness. Full nighttime intensity is equivalent to the illumination level when the parking lamps are on, and the instrument panel dimmer switch is in the highest setting.