Test B: The Control Illumination Is Inoperative/Always On

PINPOINT TEST B: THE CONTROL ILLUMINATION IS INOPERATIVE/ALWAYS ON

B1:

B2-B7:

Normal Operation
The instrument cluster monitors the medium-speed controller area network (MS CAN) bus on circuits 1848 (PK/OG) and 1847 (WH/OG) for a headlamps ON message. The headlamps ON message is generated by the smart junction box (SJB). When the instrument cluster detects a headlamps ON message, it sends a variable voltage to the module-controlled illumination sources through circuit 19 (LB/RD). The module-controlled illumination sources are grounded through circuit 57 (BK).

Possible Causes
- circuit 19 (LB/RD) open, short to voltage, or short to ground
- circuit 170 (RD/LB) short to voltage
- instrument cluster
- SJB