Steering Column: Description and Operation

STEERING COLUMN

DESCRIPTION

General
The steering column fitted to New Range Rover features fully electrical adjustment for tilt and reach. On vehicles fitted with memory seats, the steering wheel position is incorporated into the memory of the seat ECU. On certain models, a heater is fitted around the rim of the steering wheel.

OPERATION

Non-Memory Steering Column

Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fuse 23 of the passenger compartment fuse box (C0632) on an R wire. Fuse 23 (C0583) provides a constant battery feed to the steering column adjustment control unit (C1392) on an RN wire. The control unit (C1392) is earthed on an N wire.

Steering Column Switch
Movement of the steering column is controlled via the 4 way switch mounted on the LH side of the steering column. The control unit (C1392) is connected to the switch (C1393) as follows:
- If forward movement is selected, an earth path is created via the switch on an NU wire
- If backward movement is selected, an earth path is created via the switch on an NR wire
- If upwards movement is selected, an earth path is created via the switch on an NB wire
- If downwards movement is selected, an earth path is created via the switch on an NW wire.

The switch is earthed on an NB wire.

Tilt Movement
If tilt movement of the steering column is requested, the control unit (C1392) powers the height motor (C1397) via BU and UB wires.

Reach Movement
If reach movement of the steering column is requested, the control unit (C1392) powers the telescope motor (C1396) via B and U wires.

Memory Steering Column
Power Distribution
Feed from the positive battery terminal (C0192) is supplied to the seat relay and fuse 53 of the passenger compartment fuse box (C0632) on an R wire. Fuse 53 (C0583) provides a constant battery feed to the ignition switch (C0028 on V8 vehicles) on an R wire. When the ignition switch is turned to the 'ignition' position, current flows across the switch (C0028 on V8 vehicles) to the seat relay (C0585) on a G wire. The seat relay is located in the passenger compartment fuse box and is earthed (C0585) on an N wire.

Steering Column Switch
Movement of the steering column is controlled via the 4 way switch mounted on the LH side of the steering column. The seat memory ECU (C0773) is connected to the switch (C1393) as follows:
- If forward movement is selected, an earth path is created via the switch on an NU wire
- If backward movement is selected, an earth path is created via the switch on an NR wire
- If upwards movement is selected, an earth path is created via the switch on an NB wire
- If downwards movement is selected, an earth path is created via the switch on an NW wire.

The switch is earthed on an NB wire.

Seat Memory ECU
The seat memory ECU (C0773) interprets the signals received from the steering column switch (C0773) and adjusts the steering column as follows:
- If vertical adjustment is requested, the seat memory ECU provides a feed to the height motor (C1395) on a B wire
- If height adjustment is requested, the seat memory ECU provides a feed to the telescope motor (C1394) on a BU wire.

Both motors are earthed on N wires.

Steering Wheel Heater
Power Distribution
Feed from the positive battery terminal (C0192) is supplied to the steering wheel relay and fuse 53 of the passenger compartment fuse box (C0632) on an R wire. Fuse 53 (C0583) is connected to the ignition switch (C0028 on V8 vehicles) by an R wire. When the ignition switch is turned tn the 'ignition' position, current flows across the switch (C0028 on V8 vehicles) to the steering wheel relay coil (C0585) on a G wire. The steering wheel relay coil (C0585) is earthed on an N wire.

Steering Wheel Heater
The energised steering wheel relay provides a feed to fuse 29. Fuse 29 (C0582) is connected to the rotary coupler (C0374) by a GB wire, allowing the rotary coupler to provide a feed to the heated steering wheel ECU (C1948) on an N wire. The steering wheel ECU is earthed via the rotary coupler on an R then N wire.