Circuit Operation - Interior Lights Dimming

INCANDESCENT LAMPS
With the headlamp switch in HEAD or PARK, voltage is applied to the park lamp input in the panel dimming module. The dimming control on the headlamp switch varies in resistance as the dimming control is operated. The panel dimming module receives a variable input voltage based on the resistance of the dimming control. The panel dimming module provides a variable voltage via CKT 8 (GRY) to the incandescent lamps that is proportional to the voltage input from the dimming control. As the amount of voltage increases, the lamps become brighter. As the amount of voltage decreases, the lamps become dimmer.

VF DISPLAYS
The Radio, the HVAC Programmer, the Instrument Panel Cluster (IPC), and the Head-Up Display (HUD) each has a VF display. When each module receives an ignition switch to RUN input, the module will activate its VF display at full intensity. With the headlamp switch in HEAD or PARK, the Lamp Control Module (LCM) supplies a dim enable signal to the Radio, the IPC, and the HUD. when the Radio, the IPC, and the HUD receive the dim enable input, each then dims its VF display to the current dimming level. The Radio and IPC receive dimming level via CKT 8 (GRY). The HUD has a separate dimming control on the HUD Switch in the overhead console. The dimming level is received by the HUD via CKT 622 (BRN). The HVAC Programmer receives the enable and dimming level inputs from the Radio via CKT 724 (PPL/WHT).