Radio, Stereo, and Compact Disc: Description and Operation

CIRCUIT OPERATION

The Radio (including clock and cassette or equalizer option) receives its power from the Fuse when the Ignition is in "ACCY" or "RUN, and the RDO1/AUX Fuse which is hot at all times. Power from the RDO1/AUX Fuse is used to keep the clock and station memory alive when Ignition is turned "OFF."

The Radio also receives power from the Headlamp Switch (BRN and GRY wires). When the Park Lamps or Headlamps are turned "ON," power from the BRN wire (CKT 9) is used to dim the station/clock display at night. Power from the GRY wire (CKT 8) is used to vary the brightness of the panel lighting and is controlled by the Headlamp Switch rheostat.

The Radio receives its ground from G2OO and also from the grounded shield of the Antenna coaxial cable.

COMPACT DISC AND CASSETTE PLAYER
If equipped, the Compact Disc or Cassette Player is part of the Radio Unit. When operating, the same power required by the Radio is necessary for Tape or Disc Player operation:

SUBWOOFER AMPLIFIER
The Subwoofer Amplifier is controlled by the Fog Lamp/Audio Switch Assembly. The Amplifier supplies 8 volts to the Fog Lamp Audio Switch Assembly. Amplifier gain is controlled by the Gain Control in the Fog Lamp/Audio Switch Assembly. Variable voltage is fed back to the Amplifier. This voltage controls amplification of the subwoofers in the rear speakers.

ILLUMINATION
With the Radio turned on, the VF display lights to a fixed brightness. When the Park Lights or Headlights are turned on, battery voltage is applied to the "lights on input" of the Radio and the VF display dims to the present dimmer control setting. With the lights on, the Radio receives a Pulse Width Modulated (PWM) Illumination signal from the Light Switch. The PWM signals control the VF Radio illumination which varies as the dimmer control is adjusted. The Radio buttons and the face illumination is incandescent. They light when the lights are turned on, receiving power from the panel light input. The incandescent illumination brightness is controlled by the variable voltage panel light input.