Anti-theft alarm (page 2 of 3)

The same principle is true of the LH door switch, the tail door switch, and the bonnet switch. The LH door switch (C106-1) is connected to the Alarm ECU (C61-5) by a slate/white wire. The tail door switch (C615-1) is connected to the Alarm ECU (C61-16) in parallel with the RH door switch on a purple/blue wire. The bonnet switch (C7-2) is connected to the Alarm ECU (C61-9) on a orange/blue wire, and is provided an earth (C7-1) on a black wire. All 3 switches interact with the BBUS in exactly the same way as the RH door switch.

In addition to being supplied with a constant battery feed (C666-2) from fuse 2 (C580-6) of the passenger compartment fuse box, the BBUS also has its own internal power supply, and is earthed (C666-4) on a black wire.

The Alarm ECU (C61-20) also provides a feed for the ultrasonic sensor (C359-1) on a black/brown wire. The sensor is earthed (C359-2) on a black wire. When the module detects movement within the vehicle, it supplies the Alarm ECU (C61-3) with a short series of pulses on a white/black wire. Once the Alarm ECU detects these pulses, the BBUS is sounded.

To disarm the alarm system, the RF handset is used. The signal transmitted by the handset is received by the aerial. The aerial is connected to the Alarm ECU (C61-26) by an orange/slate wire.