BRAKE AND REVERSE LAMPS .................................................................. 4

Passenger Airbag

The airbag DCU (C0256) controls the feed to the passenger airbag (C0433) on a W wire. The earth path for the passenger airbag (C0433) is controlled by the airbag DCU (C0256) on a U wire.

Seat Belt Pre-tensioners RH

The airbag DCU (C0256) controls the feed to the RH pre-tensioner (C0254) on an N wire. The earth path for the RH pre-tensioner (C0254) is controlled by the airbag DCU (C0256) on an NR wire.

LH

The airbag DCU (C0256) controls the feed to the LH pre-tensioner (C0252) on an O wire. The earth path for the LH pre-tensioner (C0252) is controlled by the airbag DCU (C0256) on an OU wire.

SRS LED

Fuse 8 of the passenger compartment fuse box (C0589) provides an ignition feed to the SRS LED (C0233) on a G wire. To illuminate the LED (C0233), an earth path is provided on a YR wire via the airbag DCU (C0256). To extinguish the LED, the airbag DCU withdraws the earth path.

Diagnostic Socket

The SRS system can be interrogated using TestBook or T4 via the diagnostic socket. The diagnostic socket (C0040) is connected to the airbag DCU (C0256) by a K wire.

AIR CONDITIONING (A/C) – Td4

DESCRIPTION General

The air conditioning (A/C) system will only operate when the engine is running. The A/C system is switched on and off by pressing the switch mounted on the centre console. When the switch is pressed, an LED mounted within the switch illuminates to inform the driver the system is operational. For more information on LED operation, refer to the Interior Illumination section of this manual. + INTERIOR ILLUMINATION.

The position of the rotary heater control determines the amount of warm air from the heater matrix blended with cool air from the A/C evaporator, and hence the temperature of the air output from the heater ducts. NOTE: The blower switch must be in at least position 1 for the A/C system to operate.

For more information on heater operation, refer to the Heater Blower section of this manual. + HEATER BLOWER.

OPERATION General

Feed from the positive battery terminal (C0192) is supplied to fusible link 5, fusible link 1 and the main relay (C0632) on an R wire. All are located within the engine compartment fuse box.

The earth path for the main relay coil (C0576) is controlled by the Engine Control Module (ECM) (C0603) on a WK wire. The energised main relay provides a feed to fuse 4, which is also located in the engine compartment fuse box. For more details on main relay operation, refer to the Engine Management Systems – EDC section of the System Description and Operation Workshop manual.

Fusible link 1 is connected in series with fusible link 2, fuse 8, and fuse 9 which are also located in the engine compartment fuse box. Fuse 8 (C0576) provides a constant battery feed to the heater blower relay (C0153) on a GN then GW wire. Fuse 9 provides a constant battery feed to the compressor clutch relay, which is also located in the engine compartment fuse box.

Fusible link 2 (C0571) is connected to the ignition switch (C0028) by an NR wire. When the ignition switch is turned to the 'ignition' position, current flows across the switch (C0028) to fuse 4 of the passenger compartment fuse box (C0588) on an SU wire. Fuse 4 (C0586) provides an ignition feed to the following on G then LGS wires: The blower motor switch (C0058). The fresh/recirculated air switch (C0750). The fresh/recirculated air motor (C0006).

A/C Master Switch

When the blower switch (C0058) is turned to position 1 or higher, it provides a feed to the A/ C master switch (C0275) on an SW wire. If A/C is requested, the switch (C0275) provides a feed to the instrument pack (C0233) on an SK wire. When the instrument pack receives an A/C request from the switch, it informs the ECM (C0331) via the CAN BUS on YN (Low) and YB (High) wires. The A/C master switch is mounted on the centre console and is earthed (C0275) on a B wire.

For more information on the CAN BUS, refer to the Communication Databuses section of the System Description and Operation Workshop manual.

Compressor

When the ECM (C0331) receives an A/C request signal via the CAN BUS, it will energise the A/C compressor clutch relay by providing an earth path for the relay coil (C0576) on a UB wire. A feed from fuse 9 of the engine compartment fuse box is now able to flow across the energised relay (C0575) to the compressor clutch (C0127) on an R wire.