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

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

Normal Operation
When the parking lamps or the headlamps are on, the smart junction box (SJB) sends a reference voltage signal to the instrument panel dimmer switch on circuit VLN18 (BU/WH), which is grounded by the SJB through circuit CLN27 (WH/BN). The SJB uses the reference voltage to determine the intensity of the backlighting desired by the operator. The SJB sends a pulse-width modulated (PWM) voltage to the dimmable illumination sources on circuit VLN04 (VT/GY) based on the input received from the instrument panel dimmer switch.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Instrument panel dimmer switch
- SJB

A1-A3: