wiring LAND ROVER DISCOVERY 1999 Owner's Manual
[x] Cancel search | Manufacturer: LAND ROVER, Model Year: 1999, Model line: DISCOVERY, Model: LAND ROVER DISCOVERY 1999Pages: 1529, PDF Size: 34.8 MB
Page 829 of 1529

REAR SUSPENSION
64-20 DESCRIPTION AND OPERATION
SLS off-road mode switch
Air supply unit air control valves
Air supply unit compressor
Failure Effect
Fault in wiring harness Off-road mode cannot be selected
Failure of off-road mode switch Off-road mode is activated when switch has not
been selected
Failure Effect
Valves open or short circuit Vehicle does not level or levels unevenly
Failure Effect
Faulty relay, harness fault or compressor fault Vehicle does not level upwards
Page 867 of 1529

BRAKES
70-14 DESCRIPTION AND OPERATION
The ABS modulator is a 4 channel unit that controls the supply of hydraulic pressure to the brakes in response to
inputs from the SLABS ECU. The modulator is attached by three mounting bushes to a bracket on the LH inner front
wing, and connected to the primary and secondary hydraulic circuits downstream of the master cylinder assembly.
Three electrical connectors link the ABS modulator to the vehicle wiring.
Passages within the ABS modulator, separated into primary and secondary circuits, connect to the various internal
components that control the supply of hydraulic pressure to the brakes:
lShuttle valves and non return valves control the flow through the internal circuits.
lShuttle valve switches, connected in series to the SLABS ECU, provide a brakes on/off signal.
lA damper chamber and restrictor are included in each circuit to refine system operation.
lInlet and outlet solenoid valves control the flow to the individual brakes.
lAn expansion chamber is connected to each circuit to absorb pressure.
lA return pump is connected to both circuits to provide a pressure source.
The ABS modulator has three operating modes: Normal braking, ABS braking and active braking.
Normal braking mode
When the brake pedal is pressed, pressurised fluid from the master cylinder assembly moves the shuttle valves to
open lines 'A' and close the shuttle valve switches. Pressurised fluid then flows through the open inlet solenoid valves
to operate the brakes. The closed shuttle valve switches supply a brakes on signal to the SLABS ECU. If the SLABS
ECU determines that EBD is necessary, it energises the inlet solenoid valves for the brakes of one axle. The inlet
solenoid valves close to isolate the brakes from any further increase in hydraulic pressure.
ABS braking mode
When in the normal braking mode, if the SLABS ECU determines that ABS braking is necessary, it energises the inlet
and outlet solenoid valves of the related brake and starts the return pump. The inlet solenoid valve closes to isolate
the brake from pressurised fluid; the outlet solenoid valve opens to release pressure from the brake into the expansion
chamber and the return pump circuit. The brake releases and the wheel begins to accelerate. The SLABS ECU then
operates the inlet and outlet solenoid valves to control the supply of hydraulic pressure to the brake and apply the
maximum braking effort (for the available traction) without locking the wheel.
Active braking mode
When ETC or HDC are enabled, and the SLABS ECU determines that active braking is necessary, it starts the return
pump. Hydraulic fluid, drawn from the reservoirs through the master cylinder, shuttle valves and lines 'B', is
pressurised by the return pump and supplied to lines 'A'. The SLABS ECU then operates the inlet and outlet solenoid
valves to control the supply of hydraulic pressure to the individual brakes and slow the wheel(s).
Page 870 of 1529

BRAKES
DESCRIPTION AND OPERATION 70-17
SLABS ECU
The SLABS ECU is attached to a bracket behind the front passenger glovebox. Brake related inputs are processed
by the SLABS ECU, which then outputs control signals to the ABS modulator. Five electrical connectors interface the
SLABS ECU with the vehicle wiring.
SLABS ECU connector pin details
Connector/Pin
No.Description Input/Output
C0504
1 Battery supply Input
2 Ignition supply Input
3 Road speed Output
4 Rough road (V8 models only) Output
5 K line (diagnostics) Input/Output
7 Reverse gear Input
8 Return pump monitor Input
9 Brake warning lamp Output
10 Engine data (throttle position, torque, engine type, gearbox type) Input
11 Transfer box range Input
12 Earth-
13 ETC warning lamp Output
14 HDC switch Input
15 Neutral selected (automatic gearbox only) Input
16 HDC fault warning lamp Output
17 HDC information warning lamp Output
18 ABS warning lamp Output
C0505
1 Front left wheel speed Input
2 Front left wheel speed Input
3 Rear right wheel speed Input
4 Front right wheel speed Input
5 Front right wheel speed Input
6 Rear right wheel speed Input
7 Rear left wheel speed Input
8 Rear left wheel speed Input
C0506
1 Front left outlet solenoid valve Output
2 Front left inlet solenoid valve Output
3Earth-
4 Front right outlet solenoid valve Output
Page 872 of 1529

BRAKES
DESCRIPTION AND OPERATION 70-19
ABS sensors
The ABS sensors supply the SLABS ECU with a sinusoidal speed signal from each wheel. An inductive sensor,
installed in the hub bearing of each wheel, senses off a 60 tooth exciter ring integrated into the inner race of the hub
bearing. Each ABS sensor has a fly-lead connecting it to the vehicle wiring.
HDC switch
The HDC switch is a latching push switch installed on the fascia, in the switchpack inboard of the steering wheel.
When pushed in, the switch connects an ignition supply to the SLABS ECU to initiate HDC.
Warning indications
The SLABS ECU operates audible and visual warnings to convey brake system status.
Audible warning
A repetitive chime, at a frequency of 2 Hz, draws attention to warning lamp indications. The chime is produced on the
speaker in the instrument pack.
Warning lamps
1ABS warning lamp
2HDC fault warning lamp
3ETC warning lamp4HDC information warning lamp
5Brake warning lamp (all except NAS)
6Brake warning lamp (NAS only)
The following brake system warning lamps can be found in the instrument pack:
lA red brake graphic (all except NAS vehicles) or red BRAKE legend (NAS vehicles), to warn of low brake fluid
level, handbrake on and brake control system failure affecting EBD.
lAn amber ABS graphic, to warn of brake control system failure affecting the ABS function.
lAn amber TC graphic, to warn of brake control system failure affecting the ETC function.
lTwo inclined vehicle graphics, one amber (fault) and one green (information), to indicate operating status of HDC
and to warn of brake control system failure affecting the HDC function.
Each warning lamp is illuminated by a separate LED. The ABS, brake and ETC warning lamps are continuously on
while illuminated; the two HDC warning lamps are either continuously on or flash at a frequency of 2 Hz while
illuminated.
Page 907 of 1529

RESTRAINT SYSTEMS
75-4 DESCRIPTION AND OPERATION
Driver airbag module
The driver airbag module is located in the steering wheel and is controlled by the DCU. A bag within the module
inflates to protect the driver in the event of a collision severe enough to deploy the system.
The driver airbag module connects to the steering column wiring harness via a rotary coupler.
Within the driver airbag module is a squib which, when given the correct current by the DCU, inflates the airbag by
initiating a chemical reaction. In deployment, the airbag inflates within a fraction of a second and then deflates at a
controlled rate as the weight of the driver presses against the bag. Vents in the bag control airbag deflation.
The DCU regularly applies a test current to the driver airbag squib to confirm continuity of the ignition circuitry.
The DCU is capable of detecting a short to ground, a short to battery and an open circuit for the driver airbag module
squib. It will also identify if the configuration of the DCU differs from that actually fitted to the vehicle.
The DCU also stores the following additional information on each fault:
lA count indicating the number of times the fault has occurred.
lA start time and an end time for the fault to indicate duration of the fault.
Page 1001 of 1529

SEATS
76-5-4 DESCRIPTION AND OPERATION
Description - electric seats
General
All markets use the same electric seat system. Electically operated lumbar support is optional. The system consists
of an electrical sub-system and a mechanical sub-system.
The electrical sub-system consists of the following components:
lBCU.
lSeat power relays.
lSeat switch packs.
lSeat fore/ aft motors.
lSeat cushion front up/ down motors.
lSeat cushion rear up/ down motors.
lSeat squab motor.
lLumbar pump.
lLumbar deflate solenoid.
The mechanical sub-system consist of the following components:
lGear wheels.
lRack and pinion assemblies.
Seat power relay
Located beneath the seat, the seat power relay supplies battery voltage to the satellite fuse box. Operation of the
relays is controlled by the BCU.
Voltage to the seat power relays is from fuse 5 in the engine compartment fuse box. The BCU controls the earth for
the relay coils. Operating the seat power relays provides voltage to the satellite fuse box under each seat.
Satellite fuse box
Located beneath the seat, the satellite fuse box provides circuit protection for the wiring to the seat switches and
motors. It also protects the lumbar inflate and deflate circuits.
The seat power relay provides voltage directly to the 40A fuse in the satellite fuse box. Voltage from this fuse feeds
the seat switch pack. The 3A fuses in the satellite fuse box protect the wiring to the lumbar pump and lumbar deflate
solenoid. Voltage to the 3A fuses comes from the seat switch pack.
Page 1088 of 1529

PANEL REPAIRS
REPAIRS 77-2-21
REPAIRS
Front bulkhead assembly
Remove
1.Disconnect both battery leads, negative lead
first.
2.Disconnect leads/multiplug from alternator.
3.Remove front wing.
+ EXTERIOR FITTINGS, REPAIRS,
Wing - front - up to 03MY.
4.Remove washer reservoir.
+ WIPERS AND WASHERS, REPAIRS,
Reservoir - washer - up to 03MY.
5. Models with A/C: Remove condensor.
+ AIR CONDITIONING, REPAIRS,
Condenser.
6. Diesel models: Remove gearbox fluid cooler.
7.Remove RH and LH headlamps.
+ LIGHTING, REPAIRS, Headlamp - up
to 03MY.
8.Release headlamp levelling motors and
position aside.
9.Release headlamp wiring and position aside.
10.Remove battery.
+ CHARGING AND STARTING,
REPAIRS, Battery.
11.Remove battery tray.
12.Remove air filter assembly.
+ ENGINE MANAGEMENT SYSTEM -
Td5, REPAIRS, Air filter assembly.
+ ENGINE MANAGEMENT SYSTEM -
V8, REPAIRS, Air cleaner assembly.
13.Remove 2 earth leads from LH of front
bulkhead.
14.Remove RH horn.
+ ALARM SYSTEM AND HORN,
REPAIR, Vehicle horn.
15. Models with A/C: Release and remove A/C
pipes.
16.Remove RH and LH crush cans.
17.Remove bonnet release cable.
18.Support bonnet in open position
19.Remove bonnet locking mechanism.
20.Remove VIN plate.
21.Remove 2 bolts securing front bulkhead
assembly to chassis.
22.Remove centre braces.Repair
1.Remove existing panel(s), prepare panel joint
faces and install new panel(s) in accordance
with Panel Replacement Procedure. Punch or
drill holes in new panel for plug welding as
shown.
Refit
1.Fit centre braces.
2.Fit 2 bolts securing bulkhead to chassis and
tighten to 45 Nm (33 lbf.ft).
3.Fit VIN plate.
4.Fit bonnet locking mechanism.
5.Fit bonnet release cable.
6.Fit crush cans.
7. Models with A/C: Fit A/C pipes.
8.Fit RH horn.
+ ALARM SYSTEM AND HORN,
REPAIR, Vehicle horn.
9.Fit 2 earth leads to LH of front bulkhead.
10.Fit air filter assembly.
+ ENGINE MANAGEMENT SYSTEM -
Td5, REPAIRS, Air filter assembly.
+ ENGINE MANAGEMENT SYSTEM -
V8, REPAIRS, Air cleaner assembly.
11.Fit battery tray.
12.Fit battery. Do not connect leads.
+ CHARGING AND STARTING,
REPAIRS, Battery.
13.Fit headlamp wiring and headlamp levelling
motors.
14.Fit RH and LH headlamps.
+ LIGHTING, REPAIRS, Headlamp - up
to 03MY.
15. Diesel models: Fit gearbox fluid cooler.
16. Models with A/C: Fit condensor.
+ AIR CONDITIONING, REPAIRS,
Condenser.
17.Fit washer reservoir.
+ WIPERS AND WASHERS, REPAIRS,
Reservoir - washer - up to 03MY.
Page 1090 of 1529

PANEL REPAIRS
REPAIRS 77-2-23
Bonnet locking platform
Remove
1.Disconnect both battery leads, negative lead
first.
2.Disconnect leads/multiplug from alternator.
3.Remove front bumper assembly.
+ EXTERIOR FITTINGS, REPAIRS,
Bumper assembly - front.
4. Models with A/C: Remove condensor.
+ AIR CONDITIONING, REPAIRS,
Condenser.
5. Diesel models: Remove gearbox fluid cooler.
6.Remove RH and LH headlamps.
+ LIGHTING, REPAIRS, Headlamp - up
to 03MY.
7.Remove RH and LH repeater lamps.
+ LIGHTING, REPAIRS, Lamp - front
repeater - up to 03MY.
8.Release headlamp wiring and position aside.
9.Remove battery.
+ CHARGING AND STARTING,
REPAIRS, Battery.
10.Remove battery tray.
11.Remove air filter assembly.
+ ENGINE MANAGEMENT SYSTEM -
Td5, REPAIRS, Air filter assembly.
+ ENGINE MANAGEMENT SYSTEM -
V8, REPAIRS, Air cleaner assembly.
12.Remove RH horn.
+ ALARM SYSTEM AND HORN,
REPAIR, Vehicle horn.
13.Remove bonnet release cable.
14.Support bonnet in open position
15.Remove bonnet locking mechanism.
16.Remove VIN plate.
17.Remove centre braces.Repair
1.Remove existing panel(s), prepare panel joint
faces and install new panel(s) in accordance
with Panel Replacement Procedure. Punch or
drill holes in new panel for plug welding as
shown.
Refit
1.Fit centre braces.
2.Fit VIN plate.
3.Fit bonnet locking mechanism.
4.Fit bonnet release cable.
5.Fit RH horn.
+ ALARM SYSTEM AND HORN,
REPAIR, Vehicle horn.
6.Fit air filter assembly.
+ ENGINE MANAGEMENT SYSTEM -
Td5, REPAIRS, Air filter assembly.
+ ENGINE MANAGEMENT SYSTEM -
V8, REPAIRS, Air cleaner assembly.
7.Fit battery tray.
8.Fit battery. Do not connect leads.
+ CHARGING AND STARTING,
REPAIRS, Battery.
9.Fit headlamp wiring.
10.Fit RH and LH repeater lamps.
+ LIGHTING, REPAIRS, Lamp - front
repeater - up to 03MY.
11.Fit RH and LH headlamps.
+ LIGHTING, REPAIRS, Headlamp - up
to 03MY.
12. Diesel models: Fit gearbox fluid cooler.
13. Models with A/C: Fit condensor.
+ AIR CONDITIONING, REPAIRS,
Condenser.
14.Fit bumper assembly.
+ EXTERIOR FITTINGS, REPAIRS,
Bumper assembly - front.
15.Connect leads/multiplug to alternator.
16.Connect battery leads, negative lead last.
Page 1091 of 1529

PANEL REPAIRS
77-2-24 REPAIRS
Front cross member
Remove
1.Disconnect both battery leads, negative lead
first.
2.Disconnect leads/multiplug from alternator.
3.Remove washer reservoir.
+ WIPERS AND WASHERS, REPAIRS,
Reservoir - washer - up to 03MY.
4. Models with A/C: Remove condensor.
+ AIR CONDITIONING, REPAIRS,
Condenser.
5. Diesel models: Remove gearbox fluid cooler.
6.Remove RH and LH headlamps.
+ LIGHTING, REPAIRS, Headlamp - up
to 03MY.
7.Release headlamp levelling motors and
position aside.
8.Release headlamp wiring and position aside.
9.Remove RH horn.
+ ALARM SYSTEM AND HORN,
REPAIR, Vehicle horn.
10. Models with A/C: Release and remove A/C
pipes.
11.Remove RH and LH crush cans.
12.Remove 2 bolts securing front bulkhead
assembly to chassis.
13.Remove centre braces.
Repair
1.Remove existing panel(s), prepare panel joint
faces and install new panel(s) in accordance
with Panel Replacement Procedure. Punch or
drill holes in new panel for plug welding as
shown.Refit
1.Fit centre braces.
2.Fit 2 bolts securing bulkhead to chassis and
tighten bolts to 45 Nm (33 lbf.ft).
3.Fit crush cans.
4. Models with A/C: Fit A/C pipes.
5.Fit RH horn.
+ ALARM SYSTEM AND HORN,
REPAIR, Vehicle horn.
6.Fit headlamp wiring and headlamp levelling
motors.
7.Fit RH and LH headlamps.
+ LIGHTING, REPAIRS, Headlamp - up
to 03MY.
8. Diesel models: Fit gearbox fluid cooler.
9. Models with A/C: Fit condensor.
+ AIR CONDITIONING, REPAIRS,
Condenser.
10.Fit washer reservoir.
+ WIPERS AND WASHERS, REPAIRS,
Reservoir - washer - up to 03MY.
11.Connect leads/multiplug to alternator.
12.Connect battery leads, negative lead last.
Page 1092 of 1529

PANEL REPAIRS
REPAIRS 77-2-25
Headlamp mounting panel - RH
Remove
1.Disconnect both battery leads, negative lead
first.
2.Disconnect leads/multiplug from alternator.
3.Remove front bumper assembly.
+ EXTERIOR FITTINGS, REPAIRS,
Bumper assembly - front.
4. Models with A/C: Remove condensor.
+ AIR CONDITIONING, REPAIRS,
Condenser.
5. Diesel models: Remove gearbox fluid cooler.
6.Remove RH headlamp.
+ LIGHTING, REPAIRS, Headlamp - up
to 03MY.
7.Remove RH repeater lamp.
+ LIGHTING, REPAIRS, Lamp - front
repeater - up to 03MY.
8.Release headlamp levelling motor and position
aside.
9.Release headlamp wiring and position aside.
10.Remove battery and battery tray.
+ CHARGING AND STARTING,
REPAIRS, Battery.
11.Remove horn.
+ ALARM SYSTEM AND HORN,
REPAIR, Vehicle horn.
12.Remove RH crush can.
13.Remove 2 bolts securing front bulkhead
assembly to chassis.
14.Remove RH centre brace.Repair
1.Remove existing panel(s), prepare panel joint
faces and install new panel(s) in accordance
with Panel Replacement Procedure. Punch or
drill holes in new panel for plug welding as
shown.
Refit
1.Fit centre brace.
2.Fit 2 bolts securing bulkhead to chassis and
tighten bolts to 45 Nm (33 lbf.ft).
3.Fit crush can.
4. Models with A/C: Fit A/C pipes.
5.Fit horn.
+ ALARM SYSTEM AND HORN,
REPAIR, Vehicle horn.
6.Fit battery and battery tray. Do not connect
leads.
+ CHARGING AND STARTING,
REPAIRS, Battery.
7.Fit headlamp wiring and headlamp levelling
motors.
8.Fit repeater lamp.
+ LIGHTING, REPAIRS, Lamp - front
repeater - up to 03MY.
M77 1741A