Test A: One or More Module-Controlled Illumination Source(s) Is Inoperative

PINPOINT TEST A: ONE OR MORE MODULE-CONTROLLED ILLUMINATION SOURCE(S) IS INOPERATIVE

A1-A2:

A3:

Normal Operation
The instrument panel dimmer switch is an input to the instrument cluster through circuit 1011 (TN/OG). The instrument panel dimmer switch is grounded through circuit 570 (BK/WH). 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 and non-dimmable illumination sources are grounded through circuits 57 (BK) and 570 (BK/WH).

Possible Causes
- circuit 19 (LB/RD) open
- circuit 57 (BK) open
- circuit 570 (BK/WH) open
- rear window defrost switch
- message center switch(es)
- parking aid disable switch
- hazard flasher switch
- transmission range selector
- fog lamp switch