Interior Lamps Dimming

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The second interior lighting group includes lamps which may be dimmed. This group may use a combination of vacuum fluorescent (VF) illumination, LED illumination and incandescent lamps.

When the ignition switch is turned to the RUN position, the radio VF display turns ON at maximum brightness. When the park lamps are ON, all incandescent and LED back lighting turn ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. At the same time all VF displays dim to match the indicated dimming level. The panel dimmer switch potentiometer is an input to the body control module (BCM). When the driver selects a dimming setting by moving the I/P dimming switch potentiometer, all incandescent back lighting lamps are provided with a specific voltage. When the I/P dimmer switch is moved from MIN to MAX, all VF displays, as well as all incandescent back lighting respond from minimum intensity to maximum brightness in response to the I/P dimmer switch.

The left and right front door switch illumination is controlled, receives voltage and ground from the driver door switch and passenger switch respectively. The radio is also a GMLAN module and has full control of its illumination. The BCM, door switches, and radio communicate through GMLAN serial data for the lamp illumination commands.

The interior back lighting and indicators that are supplied through the BCM are controlled through the following control circuits:

LED Backlight Dimming Control Circuit from IS LAMPS fuse
Indicator Dimming Control Circuit from IS LAMPS fuse
Instrument Panel Lamp Dimming Control Circuit from DIM fuse

The following indicators receive voltage from the BCM and are controlled by ground from a switch or from various modules:

Tow indicator
Transfer case control switch 4WD position indicators
Fog lamp indicators
Radio
Analog clock
HVAC control assembly
Instrument panel cluster (IPC)
Driver information center (DIC)
Headlamp and panel dimmer switch
Rear parking assist (RPA) indicator

The indicators receive voltage from the BCM on the LED dimming circuit. Control for the indicators is from the various modules or switches. Voltage for the LED dimming supply circuit, instrument panel lamps dimming control circuit and the instrument panel lamps dimming supply circuit is from the BCM.

The modules controlling the above indicators are as follows:

Transfer case shift control module
Object detection module
Windshield washer solvent heater
BCM