Interior Lamps Dimming

VF DISPLAYS
With the ignition switch in RUN, the IPC will activate its VF Display. It will also coordinate display illumination for the Radio (IRC), the Cellular Telephone (PHN),and the Climate Control Panel (CCP) anytime the ignition switch is in RUN.

INCANDESCENT DIMMING 1 (INC DIM 1)
The INC DIM 1 output consists of the lamps powered by CKT 8 (GRY). They are referred to as the park lamp backlighting, because they are only active if the park lamps are on and the twilight photocell indicates darkness.

INCANDESCENT DIMMING 2 (INC DIM 2)
The INC DIM 2 output is used as a general interior light source and an illuminated entry feature that provides interior lighting. INC DIM 2 consists of lamps powered by CKT 1244 (BRN). When one or more of the following conditions occur, the INC DIM 2 lamps will be active:
^ Interior lamps switch is active.
^ Park lamps are on and the twilight photocell indicates darkness.
^ Ignition switch is in RUN and the twilight photocell indicates darkness.
^ A Class 2 message is received from the Body Control Module (PZM) indicating that the courtesy lamps are active.

DIMMING
The Instrument Panel Cluster (IPC) controls all interior dimming functions. The IPC receives an ambient light level input from the twilight photocell and determines whether it is light or dark. If the twilight photocell is inoperative, the IPC will assume a condition of darkness. Dimming of the I/P displays is only allowed when the ignition switch is in RUN, the park lamps are on, and the twilight photocell indicates darkness. If all conditions for I/P dimming are met, the IPC uses the input from the potentiometer in the headlamp switch to determine the level of dimming. The dimming level is sent to the Radio (IRC), the Cellular Telephone (PHN), and the Climate Control Panel (CCP) via a Class 2 message. These modules then adjust the dimming level of their VF display. The IPC provides dimming control of the incandescent lighting through the INC DIM 1 and INC DIM 2 outputs. The dimming level will vary based on the potentiometer in the headlamp switch whenever the park lamps are on and the twilight photocell indicates darkness, regardless of the position of the ignition switch.