Radio/Audio System Circuit Description. Opel Sintra 1999

For 1990-2009 cars

The radio receives battery voltage at all times on CKT 640 through the RADIO fuse in the underhood electrical center. The battery voltage keeps the clock and the preset station memory alive when the ignition is off. With the ignition switch in ACCY or RUN, voltage is applied to CKT 43 through the MALL/RADIO/DIC fuse in the fuse block. This enables radio operation. The radio is grounded through CKT 351. When the ignition is in RUN or ACCY, the vacuum florescent display illuminates in order to display the time or the radio frequency setting.

The instrument panel lamp dimmer controls the radio illumination. When the headlamp and the instrument panel lamp dimmer switch is in PARK or HEAD, voltage is applied through the dimmer control and CKT 230 to the radio panel lamp and the internal circuitry. When the headlamp and the instrument panel lamp dimmer switch are switched to PARK or HEAD, voltage is applied through CKT 308 to the radio. The circuit signals the internal circuitry in order to adjust the brightness of the vacuum florescent display to a level determined by the voltage of CKT 230.

### Chevrolet and Oldsmobile

The radio receives a signal from the vehicle speed sensor through CKT 389 which is the speed compensated signal. As the vehicle speed changes, the radio volume will automatically adjust the volume in order to maintain the same level of sound.

### CD Player and Cassette Player

If equipped, the CD player or the cassette player is part of the radio unit. When operating, the same power required by the radio is necessary for the tape or the CD player operation.

### Remote CD Changer

The remote CD changer receives battery voltage from the radio through CKT 43. The remote CD changer is grounded through CKT 351 to the radio.