1999 LAND ROVER DISCOVERY fog light

CONTENTS
26 CONTENTS
LIGHTING.................................................................................................. 86-2-1
ADJUSTMENTS
Headlamps beam alignment - up to 03MY ..................................................................................... 86-2-1
Headlamps beam alignment - from 03MY ...................................................................................... 86-2-2
REPAIRS
Lamp - front repeater - up to 03MY ................................................................................................ 86-2-3
Headlamp - up to 03MY .................................................................................................................. 86-2-4
Headlamp - from 03MY .................................................................................................................. 86-2-5
Lamp - tail ..................................................................................................................................... 86-2-6
Lamp - front fog up to 03MY ........................................................................................................... 86-2-6
Lamp - front fog from 03MY ............................................................................................................ 86-2-7
Housing - number plate lamp ......................................................................................................... 86-2-8
Motor - headlamp levelling ............................................................................................................ 86-2-9
Lamp - stop - centre high mounted (CHMSL) .............................................................................. 86-2-10
Lamp - tail/flasher - bumper ............................................................................................................ 86-2-10
Lamp - interior - front .................................................................................................................... 86-2-11
Lamp - interior - rear ..................................................................................................................... 86-2-11
Rheostat - panel lights dimmer ...................................................................................................... 86-2-12
Switch - hazard warning ................................................................................................................ 86-2-13
Switch - indicator and exterior lighting - combined ......................................................................... 86-2-13
Socket - accessory ........................................................................................................................ 86-2-14
Switch - front/rear fog lamps ......................................................................................................... 86-2-14
BODY CONTROL UNIT ............................................................................ 86-3-1
DESCRIPTION AND OPERATION
Description ...................................................................................................................................... 86-3-1
Operation ........................................................................................................................................ 86-3-19
REPAIRS
Body control unit (BCU) .................................................................................................................. 86-3-35
ALARM SYSTEM AND HORN.................................................................. 86-4-1
DESCRIPTION AND OPERATION
Alarm system component layout..................................................................................................... 86-4-2
Alarm system block diagram........................................................................................................... 86-4-4
Description ...................................................................................................................................... 86-4-5
Operation ........................................................................................................................................ 86-4-17
REPAIR
Switch - central door locking ......................................................................................................... 86-4-25
Switches - horn ............................................................................................................................. 86-4-25
Vehicle horn .................................................................................................................................. 86-4-26
Sounder - alarm ............................................................................................................................ 86-4-26
Sounder - battery backed-up (BBUS) ............................................................................................. 86-4-27
Switch - bonnet ............................................................................................................................. 86-4-27
Receiver - alarm system - models with sunroof ............................................................................. 86-4-28
Receiver - alarm system - models without sunroof ......................................................................... 86-4-28
Coil - passive immobilisation ........................................................................................................ 86-4-29

LIGHTING
86-2-6 REPAIRS
Lamp - tail
$% 86.40.70
Remove
1.Remove 4 screws securing tail lamp to body.
2.Disconnect multiplug from tail lamp.
3.Remove tail lamp.
Refit
1.Position tail lamp to body and connect
multiplug.
2.Secure tail lamp to body with screws.
Lamp - front fog up to 03MY
$% 86.40.95
Remove
1.Raise front of vehicle, one side.
2. For RH lamp: Remove 7 screws securing
wheel arch liner extension to liner and bumper
valance and remove liner extension.
Disconnect lamp multiplug from harness.
3. For LH lamp:Remove front bumper assembly.

+ EXTERIOR FITTINGS, REPAIRS,
Bumper assembly - front.

LIGHTING
REPAIRS 86-2-7
4.Remove 4 screws and remove lamp.
Refit
1.Fit new lamp and secure with screws.
2. For LH lamp:Fit front bumper assembly.

+ EXTERIOR FITTINGS, REPAIRS,
Bumper assembly - front.
3. For RH lamp: Connect multiplug to harness.
Fit wheel arch liner extension, secure to
bumper valance and liner with screws.
4.Lower vehicle.
Lamp - front fog from 03MY
$% 86.40.96
Remove
1.Remove the front bumper finisher.

+ EXTERIOR FITTINGS, REPAIRS,
Trim finisher - bumper - front - from 03MY.
2.Remove 3 screws securing the fog lamp to the
bumper.
3.Disconnect the fog lamp multiplug and remove
the fog lamp.
Refit
1.Position the fog lamp to the bumper, connect
the multiplug and secure with screws.
2.Fit the front bumper finisher.

+ EXTERIOR FITTINGS, REPAIRS,
Trim finisher - bumper - front - from 03MY.

LIGHTING
86-2-14 REPAIRS
Socket - accessory
$% 86.65.62
Remove
1.Remove screw securing accessory socket
escutcheon to loadspace side trim casing.
2.Release accessory socket assembly from trim
casing.
3.Disconnect multiplug and bulb from accessory
socket.
4.Remove accessory socket.
5.Release bulb holder from accessory socket.
Release accessory socket from escutcheon.
Refit
1.Fit accessory socket to escutcheon.
2.Fit bulb holder to accessory socket.
3.Position accessory socket to trim casing and
connect multiplug and bulb.
4.Fit accessory socket to trim casing and secure
with screw.
Switch - front/rear fog lamps
$% 86.65.65
Remove
1.Carefully remove switch from instrument cowl.
2.Disconnect multiplug and remove switch.
Refit
1.Position switch and connect multiplug.
2.Carefully push switch into instrument cowl.

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-9
IDM outputs
The IDM receives the following signals from the BCU using the serial datalink to provide power outputs:
Description Signal type System
Unlock all doors enable Digital Locking/ Unlocking/ Alarm
Lock passenger and rear doors enable Digital Locking/ Unlocking/ Alarm
Superlock all doors enable Digital Locking/ Unlocking/ Alarm
Lock driver's door Digital Locking/ Unlocking/ Alarm
Rear fog lamps enable Digital Exterior lighting
Daylight running lamps enable Digital Exterior lighting
LH direction indicators enable Digital Direction indicators/ Hazard warning/ Alarm
RH direction indicators enable Digital Direction indicators/ Hazard warning/ Alarm
Gear position indicator illumination Digital Illumination
Headlamp main beam indicator disable Digital Illumination
Front wiper enable Digital Wipers and washers
Rear wiper enable Digital Wipers and washers
Rear window enable Digital Power windows
Shift lever solenoid enable Digital Automatic gearbox
Transfer box solenoid enable/ Alarm sounder
relayDigital Gearbox
Heated rear window enable Digital Heated screens

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-11
Programmable options
The BCU can be programmed with a number of options to satisfy specific market requirements and customer
preferences. The options can be set using TestBook.
Function Option Details
Transmission Manual The vehicle is fitted with manual transmission.
Automatic The vehicle is fitted with automatic transmission.
Front fog lamps None The vehicle is not fitted with front fog lamps.
Main The front fog lamps will operate if the headlamps are on main beam.
No main The front fog lamps will not operate if the headlamps are on main
beam.
Interlocks None The vehicle is not fitted with key, shift or transfer box interlocks.
Shift The vehicle is fitted with key, shift and transfer box interlocks.
No transfer The vehicle is fitted with key and shift interlocks, but not a transfer box
interlock.
Daylight running lamps None The vehicle is not fitted with daylight running lamps.
No main The daylight running lamps are on if the headlamp main beams are off.
No heads The daylight running lights are on with headlamp main and dipped
beams off and the gearbox not in Park.
Programmed wash/ wipe Normal The front wipers operate if the front wash is operated.
No wipe The front wipers do not operate if the front wash is operated.
Key-in warning Disabled The ignition key in audible warning is disabled.
Enabled The ignition key in audible warning is generated if the ignition key is in
and the driver's door is open.
Electric front seats None The vehicle is not fitted with electric front seats.
Normal Electric seat adjustment is available for 45 seconds after the driver's
door opens or if the ignition is on.
Ignition II Electric seat adjustment is available if the ignition is on.
Electric front windows Driver cancel The front windows will be disabled 44 seconds after the driver's door
is opened.
All cancel The front windows will be disabled 44 seconds after any door is
opened.
No cancel The front windows will be disabled when the ignition is turned off.
Heated front screen Fitted The vehicle is fitted with heated front screens.
None The vehicle is not fitted with heated front screens.
Rear windows and sunroof Driver cancel The rear windows and sunroof will be disabled 44 seconds after the
driver's door is opened.
All cancel The rear windows and sunroof will be disabled 44 seconds after any
door is opened.
No cancel The rear windows and sunroof will be disabled when the ignition
switch is turned off.
Gear position indicator
illuminationAlways The automatic gearbox selector illumination is on when the ignition is
on.
Sidelights The automatic gearbox selector illumination is on when the ignition is
on and the sidelights are off.
Hill descent control None The vehicle is not fitted with hill descent control.
Fitted The vehicle is fitted with hill descent control.
Courtesy headlamps Disabled The vehicle is not fitted with courtesy headlamps.
Enabled The vehicle is fitted with courtesy headlamps.
Odometer error warning Disabled The odometer will not flash if there is an odometer error.
Enabled The odometer will flash if there is an odometer error.

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-15
Electric seats
The BCU controls the logical operation of the electrically operated front seats. Two modes of operation are available:

+ SEATS, DESCRIPTION AND OPERATION, Description - electric seats.
lElectric seat adjustment is enabled if the ignition is on or the driver's door is opened for a short time period.
lElectric seat adjustment is enabled if the ignition is on and the driver's door is closed.
The seats are operated by four electric motors which control the seat cushion rear up/ down, the seat cushion front
up/ down, seat cushion forward/ rearward and seat squab recline. The electrically powered lumbar adjustment in each
seat is operated by a single motorised air pump and a solenoid located on the seat squab frame. The air pump inflates
a cushion in the seat squab and the solenoid operates a valve to deflate the cushion. The seat squab and cushion
may also contain heater elements to provide heated seat operation.
The switches for electrically operated seats are located either side of the centre console.
Direction indicators and hazard warning lamps
The direction indicator lamps are operated from a three position direction indicator switch on the left hand, steering
column stalk. The BCU only allows the lamps to work as direction indicators when the ignition switch is in position II.
The BCU also controls the lamps to operate as hazard warning lamps and as a visual warning for the anti-theft system,
in which cases all lamps flash simultaneously irrespective of the ignition switch position.
System control of the direction indicators and hazard warning lamps is provided by the BCU operating with the IDM
and two electronic relays located in the passenger compartment fuse box. The IDM and relays are integral parts of
the passenger compartment fuse box and cannot be serviced individually. The serial data bus is used for
communication of status and operation requests between the BCU, IDM and instrument pack.
The hazard warning lamps are operated from a latching pushbutton switch located on the fascia.
All direction indicator/ hazard warning lamp bulbs are rated at 5 Watts.
Headlamps
The BCU contains a feature which allow the vehicle headlamps to be turned on when the remote transmitter is
pressed (courtesy headlamps).
For markets with daylight running lamps, the BCU controls the logical operation of the daylight running lamps. Options
are daylight running lamps are on if the main beam headlamps are off, or the daylight running lamps are on with main
and dipped beam off and the gearbox not in Park.
Front fog lamps
For markets with front fog lamps fitted, the BCU controls the operation of the front fog lamps. Options can be selected
so that the fog lamps will operate with or without the headlamps on main beam.
Instrument pack
The BCU communicates with the instrument pack via a serial data bus.

+ INSTRUMENTS, DESCRIPTION AND OPERATION, Description.
lThe instrument pack provides the BCU and IDM with details of vehicle speed.
lSignals are provided from the IDM to the instrument pack and BCU when the direction indicator lamps are active.
lFor certain markets, the BCU provides a signal to the instrument pack for indicating when the transfer box is in
neutral.
lThe IDM can signal the instrument pack to illuminate a trailer warning lamp. This operates when the IDM senses
that the current drawn by the indicator circuit exceeds a preset threshold.
lThe odometer reading displayed on the instrument pack LCD screen is also stored in non volatile memory in the
BCU. Whenever the ignition is turned from position I to position II, the instrument pack and the BCU compare
their stored values.
lThe gear selector position is displayed on the instrument pack LCD screen under the direction of the BCU.
Starting
The starting system comprises a starter motor and solenoid located at the rear right hand side of the engine. A starter
relay controlled by the BCU is used to supply battery power for starter solenoid operation. The starter motor receives
its feed directly from the battery.

BODY CONTROL UNIT
86-3-28 DESCRIPTION AND OPERATION
Courtesy headlamps
This feature activates the headlamps for 30 seconds when the lock button on the remote transmitter is held down for
longer than 1 second. The headlamps will extinguish if the BCU receives either a lock or an unlock signal from the
remote transmitter.
The BCU checks the status of the following inputs to determine the correct qualifying conditions for requesting
courtesy headlamps:
lIgnition state.
lRemote locking request.
lRemote unlocking request.
lLazy locking request.
If the ignition is off and a lazy locking request is received, the courtesy headlamps are switched on and an internal
timer is turned on in the BCU which operates for 30 seconds. If the 30 second timer expires or a request for remote
locking or remote unlocking is received, the courtesy headlamps will be turned off.
When main beam is selected, the IDM also provides a signal to the instrument pack to switch on the main beam
warning lamp. An additional signal 'main beam indicator disable' is used to prevent the daylight running lamps
illuminating the main beam indicator when the main beam is in the daylight running lamp state and the main beam
indicator disable signal is on.
Lights on alarm
The lights on alarm in the instrument pack operates when the driver's door is open and the side lamps or headlamps
are on. The system uses inputs from the driver's door switch and the lighting switch to determine the logical conditions
that need to occur for switching on the alarm. The BCU carries out the logic operation and communicates with the
instrument pack using the serial data bus; the instrument pack will be requested to sound the alarm if the logic inputs
indicate that the driver's door is open with the lights still on.
Supply voltage is provided through the lighting switch to the IDM which acts as the signal line to indicate that the lights
are on for the logic circuits in the IDM and BCU. When the driver's door is opened, a second feed is supplied to the
BCU through the driver's door switch to indicate the condition. In this logic condition (lights on and driver's door open)
the BCU signals the instrument pack to operate the audible warning. If the lights are switched off or the driver's door
is closed the logic condition will be changed and the audible warning will be switched off.
Daylight running lamps
The BCU operates the daylight running lamps (where fitted) via the IDM. The daylight running lamps option can be
programmed in one of three states dependent on market/ customer requirements, these are:
lOption 1– no daylight running lamps.
lOption 2 – on with main beam off.
lOption 3 – on with main and dipped beam off and gearbox not in Park.
The BCU will ensure the logical conditions are satisfied for the lamps to operate under the set conditions. The BCU
checks the status of the following inputs to determine the logic action for providing an output to the daylight running
lamp relay:
lMain beam state.
lEngine running (link from instrument pack).
lDipped beam.
lGearbox state.
A voltage supply is fed to the coil of the daylight running lamp relay and the IDM. When the preconditions are satisfied
for daylight running lamp operation, the BCU sends a signal for the IDM to complete the circuit to earth to switch on
the daylight running lamps. The logical inputs are checked to ensure that the engine is running before switching the
relay to turn on the daylight running lamps. The engine running signal has to be present for at least 2 seconds before
the daylight running lamp relay can be switched on.
Fog lamps
The BCU operates the rear fog lamps and the front fog lamps (where fitted) via the IDM. The BCU front fog lamp
operation can be programmed to operate under one of three set conditions. The BCU will ensure the logical conditions
are satisfied for the lamps to operate under the set conditions.