Operation CHARM: Car repair manuals for everyone.

Circuit Operation

The radio receives battery voltage at all times on circuit 640 through the RADIO-HVAC Fuse to keep clock and preset station memory alive when the ignition is off. With the ignition switch in ACCY or RUN, voltage is applied to circuit 43 through the RADIO Fuse to enable radio operation. The radio is grounded through circuit 351. When the ignition is in RUN or ACCY, the Vacuum Fluorescent (VF) display illuminates to display the time or radio frequency setting.

When the headlamp switch is in PARK or HEAD, voltage is applied through the dimmer control and circuit 8 to the radio panel lamp and the internal circuitry. When the headlamp switch is switched to PARK or HEAD, voltage is applied through circuit 32 to the radio, signaling the internal circuitry to adjust the brightness of the vacuum fluorescent display to a level determined by the voltage of circuit 8.

Compact Disc and Cassette Player
If equipped, the Compact Disc (CD) or cassette player is part of the radio unit. When operating, the same power required by the radio is necessary for tape or CD player operation.