Test A: The Control Illumination Is Inoperative - All Hardwired Illumination

PINPOINT TEST A: THE CONTROL ILLUMINATION IS INOPERATIVE - ALL HARDWIRED ILLUMINATION

A1-A3:

A3-A5:

A5-A7:

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 hardwired dimmable illumination sources through circuit VLN04 (VT/GY) (Navigator only) and/or circuit VLN18 (BU/WH) (Expedition) (Navigator auxiliary climate control assembly).

The SJB also sends a message over the network to the audio unit, the DVD player, the climate control module, and the instrument cluster 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 DTC U0140 in continuous memory (except the climate control module) and defaults the backlighting to full intensity.

DTC B2A32 - is an on-demand DTC that sets when the SJB detects an open on the LED backlighting output circuit. This DTC also sets when fuse 10 (15A) has failed or is removed.

DTC B2A33 - is a continuous and on-demand DTC that sets when the SJB detects a short to ground on the LED backlighting output circuit.

DTC B29B7 - is an on-demand DTC that sets when the SJB detects an open on the white lighting output circuit. This DTC also sets when fuse 10 (15A) has failed or is removed.

DTC B29B8 - is a continuous and on-demand DTC that sets when the SJB detects a short to ground on the white lighting output circuit.

Possible Causes
- Fuse
- Circuitry
- Auxiliary climate control assembly
- SJB