Operation

Horn

OPERATION

Horns
Feed from the positive battery terminal (C0192) is supplied to fusible link 4, fuse 6, and the horn relay coil (C0632) on an R wire. All are located in the engine compartment fuse box. The horn relay coil (C0576) is connected to the horn switches (C1254) via the rotary coupler (C0082) by a PY then P wire. The horn switches are normally open switches. When either of the horn switches are depressed, the switch contacts close and an earth path is created via the rotary coupler (C0082) on a B wire.

The horn relay (C0576) is now energized, and is able to provide a feed from fuse 6 to the LH horn (C0003) on a PB wire. The horn relay (C0570) also provides a feed to the RH horn (C0004) on a PB wire. Both horns are earthed on B wires.

Alarm Trigger
Fusible link 4 (C0574) provides a constant battery feed to the Central Control Unit (CCU) (C0593) via the passenger compartment fuse box (C0587) on an NW wire. If the alarm is triggered, the CCU (C0430) provides an earth path for the relay coil (C0576) on a PY wire.

The horns relay is now able to provide a feed to the horns as described above.

By pulsing the earth path for the horn relay on and off, the CCU is able to control operation of the horns.