IPC Dimming

The IPC displays are dimmable with parklamps or headlamps on, via the headlamp switch. Only the indicators, turn signals, and hi beam telltales are non-dimmable. The IPC monitors the Dimming Potentiometer, Parklamp, Headlamp and Twilight Sentinel inputs to determine if dimming should be active and, if active, at what level.

The IPC generates three different pulse-width modulated (PWM) outputs which correlate to the requested dimming level from the dimming potentiometer. The IPC Also determines the appropriate vacuum fluorescent (VF) dimming level and sends this information to the IRC, CCP and Cellular Telephone (if applicable) via the Class 2 serial data bus.
The IPC Also supplies a 16-volt power feed to the Radio (IRC) for VF intensity stabilization. This is typically only available when the ignition switch is in "UNLOCK" or "RUN," but may be "ON" when the DIC is active.