Interior Lamps Dimming

The third group includes the following 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 HVAC control head assembly
^ The radio
^ The Instrument Panel Cluster (IPC)
^ The headlamp switch assembly
^ The hazard warning switch
^ The ashtray lamp
^ The shift indicator lamp
^ The Driver Information Center (DIC) switches
^ The traction control switch
^ The heated seat and the memory seat switches
^ The steering wheel controls

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 sunload sensor indicates low light conditions, all incandescent back lighting and Vacuum Fluorescent (VF) displays turn on at the dimming level indicated by the IP dimmer switch. The rear fuse block supplies battery positive voltage to the normally open switch of the PRK LP relay. The Dash Integration Module (DIM) supplies battery positive voltage to the PRK LP relay coil controlled positive voltage circuit. The DIM also provides ground to the control circuit of the PRK LP relay coil. When the DIM energizes the park lamp relay, current flows through the PRK LP relay switch to the DIMR fuse to the instrument panel lamp fuse supply voltage-1 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 instrument cluster provides a 54 volt supply to the Instrument Panel Integration Module (IPM). The supply circuit is used to power the HVAC vacuum fluorescent (VF) display.

The incandescent back lighting for the doors also operates in response to a class 2 message regarding dimming intensity. The IPM sends the message to the appropriate door module regarding dimming intensity.

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.