Interior Lamps Dimming

The third group includes lamps which may be dimmed. This group may use a combination of Vacuum Fluorescent (VF) illumination and of incandescent lamps.
^ The door switches and the window switches
^ The driver information center
^ The heated seat switches
^ The HVAC control head assemblies
^ The radio
^ The Instrument Panel Cluster (IPC)
^ The IP dimmer switch
^ The steering wheel control switches
^ The traction control switch
^ The trip odometer and reset switch

When the ignition switch is turned to the ON position, the vacuum fluorescent (VF) displays turn on at maximum brightness. When the park lamps are on and the ambient light sensor indicates low light conditions, all incandescent back lighting turn on at the dimming level indicated by the IP dimmer switch. At the same time all vacuum fluorescent (VF) displays dim to match the indicated dimming level. The rear fuse block supplies battery positive voltage to the normally open switch of the park lamp relay. The Dash Integration Module (DIM) supplies battery positive voltage to the park lamp relay control circuit. The DIM also provides ground to the relay control circuit. When the DIM energizes the park lamp relay, current flow from switch goes through the DIMR fuse to the incandescent dimming circuit of the DIM. With the park lamps on, the DIM sends proportional voltage to the circuit in response to an input from the Instrument Panel Integration Module (IPM). The potentiometer of the IP dimmer switch receives a reference voltage and ground from the IPM. The potentiometer is an input to the IPM. When the driver selects a dimming setting, the IPM responds with a message to the DIM indicating this setting. All vacuum fluorescent (VF) lamps and all incandescent back lighting lamps have voltage and ground at G200 and at G201. When the IP 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 IP dimmer switch.

The incandescent back lighting for the doors also operate in response to a class 2 message regarding dimming intensity. The IPM sends the message to the Driver Door Module (DDM. The DDM sends an SBI message regarding dimming intensity to all the other door modules.

The driver may select parade mode by manually turning on the park lamps during daylight conditions. The front park lamp circuit supplies voltage to the instrument panel cluster, radio and HVAC assembly for a park lamp on input, and the displays will become full bright.