Dimmable Backlighting

When the parking lamps are on, the SJB  monitors the input from the instrument panel dimmer switch. The SJB  sends a Pulse Width Modulated (PWM) voltage to the dimmable switches based on input received from the instrument panel dimmer switch.

The SJB  also sends a message over the Controller Area Network (CAN) to the Front Controls Interface Module (FCIM) (vehicles without navigation), the Front Display Interface Module (FDIM) (vehicles without navigation), the HVAC module (vehicles with navigation), the Audio Control Module (ACM) (vehicles with navigation), the Rear Entertainment Module (RETM) (if equipped) and the Instrument Cluster (IC) to indicate the backlighting intensity level. If the receiving module receives invalid backlighting data from the SJB  for 5 seconds or less, the receiving module defaults the backlighting to the last setting.

If the receiving module does not receive the backlighting status message from the SJB  or if the data received is deemed invalid for more than 5 seconds, the receiving module sets a missing message related DTC in continuous memory (except the HVAC module) and defaults the backlighting to full nighttime intensity.