Normal Operation

Based on input received from the instrument panel dimmer switch, the Smart Junction Box (SJB) sends a Pulse Width Modulated (PWM) voltage to the dimmable illumination switches.

• DTC B29B7 (White Lighting Output Circuit Open) - an on-demand DTC that sets when the SJB detects an open from the backlighting output circuit.
• DTC B29B8 (White Lighting Output Circuit Short to Ground) - a continuous and on-demand DTC that sets when the SJB detects a short to ground from the output circuit. This DTC also sets when fuse 10 (15A) has failed or is removed.

This pinpoint test is intended to diagnose the following: 

• Fuse
• Wiring, terminals or connectors
• SJB