Normal Operation

The headlamp switch supplies the instrument cluster with the headlamp switch position status. For additional information on the headlamp switch operation, refer to EXTERIOR LIGHTING . The instrument panel dimmer switch provides the instrument cluster with the dimming control status through signal circuit 8-LE10 (WH/BK) and return circuit 9-LE10 (BN/YE). The instrument cluster sends the illumination message to the front electronic module (FEM) over the communication network, based upon the instrument panel dimmer switch position. The FEM is supplied with illumination power through circuit 29S-DK22 (OG/YE) whenever the switched system power (SSP) is energized. For additional information on the SSP operation, refer to EXTERIOR LIGHTING . When the headlamp switch is in the PARK, HEADLAMP, or AUTOLAMP ON position, the instrument cluster sends the FEM an illumination message and the FEM, in turn, provides a pulse width modulation (PWM) signal to the auxiliary junction box through circuit 64S-LH2 (BU/RD) and then to the dimmable backlighting sources. If the dimmer switch signal and return circuits or the dimmer switch are open, the instrument cluster will default the FEM to maximum intensity.