Circuit Operation

The electronically tuned Radio receives its power from the RDO-2 Fuse and CKT 43: when the Ignition is in "ACCY" or "RUN." The clock and memory circuits receive power from RD01/AUX Fuse and CKT 640 at all times. The Radio is grounded through CKT 1051. When the Ignition is in "RUN" or "ACCY," the vacuum fluorescent display illuminates to display the time or Radio frequency setting.

The Radio illumination is controlled by the Instrument Panel Lamp Dimmer. When the Headlamp Switch is in "PARK" or "Head," voltage is applied through the Dimmer Control and CKT 8 to the Radio panel light and the internal circuitry. When the Headlamp Switch is switched to "PARK" or "HEAD," voltage is applied through CKT 9 to the Radio, signalling the internal circuitry to adjust the brightness of the vacuum fluorescent display to a level determined by the voltage of CKT 8.