AM/FM ESR or AM/FM/Cassette ESC

OPERATION

Redundant Radio Control and Radio Knob Illumination
With the Main Light Switch in the "OFF" position, the Redundant Radio Control and Radio knob illumination bulbs are also off. With the Main Light Switch in "PARK" or "HEAD", battery voltage is applied to the I/P Dimming Rheostat. The I/P Dimming Rheostat controls the brightness of the Redundant Radio Control and Radio knob illumination bulbs by determining the voltage present on circuit 19 (LB/R). See Instrument Panel Illumination for more information.

Radio Time/Frequency Display Illumination
With the Main Light Switch in the "OFF" position, battery voltage is present at the Radio on circuit 434 (LB/BK). The Radio Time/Frequency Display illuminates at full brightness for maximum daytime visibility. With the Main Light Switch in "PARK" in "HEAD", battery voltage is applied to the I/P Dimming Rheostat. The I/P Dimming Rheostat controls the brightness of the Time/Frequency Display by determining the voltage present on circuit 434 (LB/BK). See Instrument Panel Illumination for more information.

Radio Memory and Operating Power
Voltage is present at the Radio at all times through Fuse 8 and circuit 54 (LG/Y). This constant power to the Radio maintains clock and station preset memory functions.

With the Ignition Switch in "ACC" or "RUN", voltage is also present at the Radio through Fuse 11 and circuit 137 (Y/BK). When the Radio is turned on, current flows through circuit 137 (Y/BK) and the Radio circuits to ground. The Radio turns on.

AM/FM ESR and AM/FM/Cassette ESC Radios
In the AM/FM ESR and AM/FM/Cassette ESC Radio systems, the Radio contains an internal amplifier, which directly powers all four speakers.

Power Antenna
The Power Antenna is controlled by the Power Antenna Module. Voltage is present at the Power Antenna Module at all times on circuit 54 (LG/Y). With the Ignition Switch in "ACC" or "RUN", voltage is also present at the Power Antenna Module on circuit 137 (Y/BK). The Power Antenna Module controls operation of the reversible Power Antenna Motor, according to inputs provided by the Radio on circuit 747 (O/LB), the Ignition Switch on circuit 137 (Y/BK), and the Starting System on circuit 33 (W/PK).

When the Power Antenna Module applies voltage to circuit 745 (R/PK), the Power Antenna Motor runs to extend the antenna mast. When the Module applies voltage to circuit 746 (DG/Y) current flows through the Power Antenna Motor in the opposite direction and the mast retracts.