Normal Operation

Based on input received from the instrument panel dimmer switch, the Smart Junction Box (SJB) sends a pulse-width modulated voltage to the hardwired dimmable illumination sources through circuit VLN04 (VT/GY) (Navigator only) and/or circuit VLN18 (BU/WH) (Expedition) (Navigator auxiliary climate control assembly).

• DTC B2A32 (LED Backlighting Output Circuit Open) - is an on-demand DTC that sets when the SJB  detects a short to voltage from the backlighting output circuit.
• DTC B29B7 (White Lighting Output Circuit Open) - is an on-demand DTC that sets when the SJB  detects a short to voltage from the white lighting (backlighting) output circuit.

This pinpoint test is intended to diagnose the following: 

• Wiring, terminals or connectors
• SJB