Interior Lamps Dimming
The second group includes lamps which may be dimmed. This group may use a combination of vacuum fluorescent (VF) illumination and incandescent lamps.
When the ignition switch is turned to the RUN position, the radio's vacuum fluorescent (VF) displays turn on at maximum brightness. When the park lamps are on, all incandescent back lighting turn on at the dimming level indicated by the I/P dimmer switch. At the same time all vacuum fluorescent (VF) displays dim to match the indicated dimming level. The panel dimmer switch potentiometer is an input to the 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 vacuum fluorescent (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 following switches and components have back lighting when the park lamps are on:
- The instrument panel cluster (IPC)
- Radio, front and rear
- Window and heated seat switches
- Garage door opener switch
- Selectable ride switch
- Roof beacon switch
- Power take off (PTO) switch
- Headlamp leveling switch
- Rear wheel steering mode select switch
- HVAC control assembly
- Headlamp and panel dimmer switch
- Transfer case shift control switch
- PSIR disable switch
- PRNDL lamps
- Traction control switch
- Steering wheel control switches
- Fog lamp switches
The left and right front door switch illumination is controlled, receives voltage and ground from the drivers door module (DDM) and the passenger door module (PDM) respectively. The radio is also a class II module and has full control of its illumination. The BCM, DDM, PDM, and radio communicate through class II serial data for the lamp illumination commands
The I/P cluster illumination lamps receive voltage and are controlled by the BCM on the instrument panel lamps dimming supply voltage circuit. Ground for the instrument panel lamps is at G203.
The various switches, HVAC control assembly, and the PRNDL lamps receive voltage and are controlled by the BCM on the instrument panel lamps dimming control circuit. Ground for the rear window switches is at G302 and G306. Ground for the traction control switch, steering wheel controls, and the rear window/wiper switch is at G108. Ground for the remaining switches is at G203.
The following indicators receive voltage from the BCM and are controlled by ground or from various modules:
- Rear wheel steering mode select switch indicators
- Fog lamp switch indicators
- All multifunction accessory switch indicators
- Selectable ride switch
- Roof beacon
- Traction control switch traction control OFF indicator
- Transfer case control switch position indicators
Ground/control for the indicators is from various modules or ground. Voltage for the LED dimming supply circuit, instrument panel lamps dimming control circuit and the instrument panel lamps dimming supply circuit is from the TBC A fuse in the instrument panel fuse block directly through the BCM to these circuits. A short to ground on only the instrument panel lamps dimming control circuit will open the fuse.
The modules controlling the above indicators are as follows:
- Rear wheel steering control module
- Electronic suspension control module
- Transfer case shift control module
- Body control module (BCM)