bulb LAND ROVER DISCOVERY 1999 User Guide

LIGHTING
86-2-10 REPAIRS
Lamp - stop - centre high mounted
(CHMSL)
$% 86.41.32
Remove
1.Remove 2 screws securing lamp cover and
remove cover.
2.Disconnect Lucar connectors from lamp bulb
holder.
3.Remove 2 nuts securing lamp to rear screen
and remove lamp.
Refit
1.Fit new lamp to screen and secure with nuts.
2.Connect Lucar connectors to lamp bulb holder.
3.Fit lamp cover to lamp and secure with screws.
Lamp - tail/flasher - bumper
$% 86.41.42
Remove
1.Release tail lamp from bumper.
2.Disconnect multiplug and remove lamp.
Refit
1.Position tail lamp, connect multiplug and
secure lamp to bumper.

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
86-3-12 DESCRIPTION AND OPERATION
Seatbelt warning lamp Timed The warning lamp is on for 6 seconds after the ignition is turned on.
Buckle The warning lamp is on for 6 seconds after ignition is turned on or until
the buckle is fastened.
Ignition II If the buckle is unfastened when the ignition is turned on then the
warning lamp comes on for 6 seconds.
Disable The warning lamp is not used.
Seatbelt audible warning Timed The audible warning is on for 6 seconds after the ignition is turned on.
Buckle The audible warning is on for 6 seconds after the ignition is turned on
or until the buckle is fastened.
Ignition II If the buckle is unfastened when the ignition is turned on then the
audible warning is on for 6 seconds.
Disable The audible warning is not used.
Bulb failure warning Disabled Direction indicator bulb failure detection is disabled.
Enabled Direction indicator bulb failure detection is enabled.
Superlocking None Superlocking is not available.
Double The vehicle will superlock on a double press of the remote transmitter
or double key turn.
Single The vehicle will superlock on a single press of the remote transmitter
or a single key turn.
No key The vehicle will superlock on a single press of the remote transmitter
but not with the key.
Door unlocking Not SPE The SPE (Single Point Entry) function is not used. All doors unlock on
a remote transmitter press.
SPE Only the driver's door unlocks on the first remote transmitter press, all
other doors on the second press.
Alarm disarming Always Operation of the key in the driver's door always disarms the vehicle.
Key only Operation of the key in the driver's door only disarms the vehicle if it
was locked with the key.
Key never The security system is not disarmed by the key (except for EKA).
Inertia switch No hazards Operation of the inertia switch does not operate the hazard warning
lamps.
Hazards Operation of the inertia switch operates the hazard warning lamps.
Speed locking Disabled Speed related locking is disabled.
Enabled Speed related locking is enabled. The door locks are disabled when
the vehicle is moving.
Volumetric sensing Disabled Volumetric sensing is disabled.
Enabled Volumetric sensing is enabled.
Alarm Disabled The vehicle is not fitted with a security system.
Enabled The vehicle is fitted with a security system.
Passive immobilisation Disabled Passive immobilisation is disabled.
Enabled Passive immobilisation is enabled.
Hazard warning lamps Disabled The hazard warning lamps do not flash on security system arm,
disarm or trigger.
Enabled The hazard warning lamps flash on security system trigger only.
All The hazards flash on security system arm, disarm and trigger.
Mislocking audible
warningDisabled Mislock audible warnings are disabled.
Enabled Mislock audible warnings are enabled.
Alarm sounder Alarm Audible warnings are given by the security system sounder only.
Both Audible warnings are given by both the security system sounder and
the vehicle horn.
Vehicle Audible warnings are given by the vehicle horn only.
BBUS Audible warnings are given by the security system sounder, vehicle
horn and BBUS.
Disabled Audible warnings are not given. Function Option Details

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
86-3-26 DESCRIPTION AND OPERATION
Electric seats
The BCU can be programmed to operate the electric seats according to one of three options:
lOption 1 – no electric seats.
lOption 2 – normal.
lOption 3 – operates with ignition only.
To determine when to provide an output to the passenger and drivers seat enable relay, the BCU checks the condition
of the following inputs:
lIgnition state.
lTransit mode.
lDriver's door open.
The electrically controlled seats are operated when the ignition switch is in position I or II or for a predetermined period
when the driver's door is open. If the ignition state is in crank, the seat enable relay is off. If the ignition state is off and
the driver's door open input is off, the seat enable relay is off. If the ignition state is off and the driver's door open input
is on and transit mode is on, the seat enable relay output is off.
The power supply to each seat switch pack is powered from a power seat relay located on the underside of each seat
frame. The feed from the relay is protected by a fuse located in a satellite fuse block located adjacent to the power
seat relay. The fuse block also contains two additional fuses which are used to protect the feeds to the lumbar pump
and solenoid.
With the ignition switch in position I or II or the driver's door open, the BCU provides an earth path for the coils of the
LH and RH power seat relays, energising the relays and closing the contacts. If the driver's door input signal is on for
longer than 45 seconds with the ignition switched off, the seat enable relay is switched off.
Direction indicators and hazard warning lamps
The BCU supplies reference voltages for the LH and RH indicators. When the direction indicator switch is used to
select the LH or RH indicator position, an earth path is completed which signals the BCU that a request for direction
indicator operation has been made. The BCU then communicates this request to the IDM which supplies an earth
path for the coil of the relevant relay (LH or RH indicator relay). When the relay coil is energised, the relay contacts
close and a voltage supply is provided via a resistor to the relevant direction indicators. The IDM controls the timing
of the flash operations by continually removing and restoring the earth path to the direction indicator relay coil.
The BCU checks for the following inputs for performing the logic operations associated with the direction indicator
lamps:
lIgnition state.
lRH indicators selected.
lLH indicators selected.
lHazards selected.
lInertia switch hazard request.
lOne short indicator flash request (anti-theft system arming).
lTwo short indicator flash request (superlocking).
lOne long indicator flash request (anti-theft system disarming).
lAlarm flashing indicators (anti-theft alarm triggered).
The following outputs are provided by the BCU as a result of the inputs received and the logical operations performed:
lRH indicators enable.
lLH indicators enable.
lDirection indicator left message (link to IDM).
lDirection indicator right message (link to IDM).
Direction indicator lamp failure detection
The BCU uses the following logic inputs to determine if there is a direction indicator bulb failure or if the presence of
a trailer is detected. The BCU uses the information to decide which output to enable at any particular instance:
lRight direction indicators requested.
lLeft direction indicators requested.
lRH indicators current sense.
lLH indicators current sense.

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-27
If a direction indicator bulb failure or a trailer presence is detected, the following outputs can be generated depending
on the BCU logic states:
lTrailer detected.
lBulb failure detected.
lDirection indicator short circuit.
lDirection indicator relay stuck.
The BCU can be configured whether or not to provide bulb failure warnings.
When the direction indicators are operating, instrument pack direction indicators flash in sequence with the exterior
direction indicators. If a failure of an indicator bulb occurs, the corresponding instrument pack indication lamp will flash
quickly to warn of the problem.
The IDM monitors the current drawn through the circuit to detect for the occurrence of a lamp failure. If an indicator
lamp fails, the IDM detects the drop in current drawn through the resistor and operates the indicator relay at a faster
speed. The fast flash is demonstrated on the instrument pack direction indicator warning lamps to bring attention to
the driver that a direction indicator bulb failure has occurred. The current sense for the related indicator lamps (RH or
LH) are checked when a direction indicator request has been made that lasts for at least 160 ms. The current level
sensed is relative to the number of working bulbs and determines the request generated by the BCU.
The output is signalled to the instrument pack using the serial communications link. If the hazard warning lamps are
operating, both sets of direction indicators are checked using the current sensing functions to check the number of
bulbs on each side of the vehicle.
If the BCU detects that a direction indicator request has not been made, but one or other of the current sense inputs
indicate that current is flowing, a 'Relay stuck' output is generated.
Hazard lamps
The BCU controls the operation of the hazard warning lamps via the IDM and dedicated relays. The hazard warning
lamps are activated under the following conditions:
lThe vehicle is locked and the security system is set (the hazard warning lamps flash three times if the
superlocking feature is used, once if not).
lThe vehicle is unlocked (the hazard warning lamps flash once for a duration of two seconds).
lThe anti-theft alarm system is triggered (the hazard warning lamps flash in phase with and for the duration of the
audible warning).
lThe hazard warning switch is pressed (the hazard warning lamps flash until the hazard warning switch is pressed
for a second time).
lThe inertia switch is triggered (the hazard warning lamps flash until the inertia switch has been reset).
The hazard warning lamp operation may differ dependent on market and customer configuration options.
The hazard warning lamps are operated from a latching pushbutton switch located on the fascia. When the switch is
pressed, both left and right indicator lamps in the instrument pack flash to show that the hazard warning lamps are
operating and all hazard warning lamps flash simultaneously. If a trailer is fitted, the ICM detects this and a trailer
symbol in the instrument pack also flashes to show correct operation of the trailer direction indicators and hazard
warning lamps.
The BCU supplies a reference voltage to the hazard warning switch. When the hazard warning switch is operated an
earth path is completed which signals the BCU that a request for hazard lamp operation has been made. The BCU
then sends a signal to the IDM via the serial data bus to communicate the request. The IDM supplies an earth path
for both direction indicator relay coils simultaneously so that the hazard warning lamps are turned on concurrently.
The IDM controls the timing of the flash operations by continually removing and restoring the earth path to both
direction indicator relay coils simultaneously.
Number of working bulbs Request generated
3 Trailer detected
2 None (bulbs okay)
1 Bulb failure detected
0 Direction indicator short circuit detected

ALARM SYSTEM AND HORN
REPAIR 86-4-29
Coil - passive immobilisation
$% 86.77.35
Remove
1.Remove steering column nacelle.

+ STEERING, REPAIRS, Nacelle -
steering column.
2.Release passive coil from steering lock.
3.Disconnect illumination bulb holder and
multiplug and remove passive coil.
Refit
1.Position passive coil, connect multiplug and
illumination bulb holder.
2.Fit passive coil to steering lock.
3.Fit steering column nacelle.

+ STEERING, REPAIRS, Nacelle -
steering column.

WINDOWS
DESCRIPTION AND OPERATION 86-5-5
Front window switches
The front window switches are non-latching rocker switches located in the center console. The front window switches
contain illumination bulbs that operate when the side lamps or headlamps are on.
The front window switches provide earth signals to the BCU. The BCU determines which direction to operate the front
window motors.
TestBook will monitor the real time status of the front window switches.

DRIVING AIDS
DESCRIPTION AND OPERATION 86-8-9
PDC Switch
The PDC switch is located in the instrument pack cowl, below the fuel flap release switch. The switch has a
momentary, non-latching action, which switches a positive output from the PDC ECU to ground when pressed. This
signal is used by the ECU to switch the PDC between the activated and de-activated conditions. The switch is
connected to the PDC ECU via a harness connector which is integrated into the vehicle body harness.
The switch contains an LED. The LED illuminates for approximately 3 seconds when the ignition is switched to
position II for a bulb check. The bulb check is controlled by logic within the PDC ECU. When the system is active (i.e.
obstacle detected), the LED illuminates to show the active condition.
When the PDC is switched from the off condition to the active condition, the LED is illuminated briefly, along with a
chime from the sounder, to signal that the system has been activated.
If a fault exists in the PDC system, the ECU flashes the LED continuously, when the switch is pressed to activate the
system.

INSTRUMENTS
DESCRIPTION AND OPERATION 88-5
Description
General
The instrument pack consists of four analogue dials, four warning lamp packs and a Liquid Crystal Display (LCD)
odometer.
The four dials are used to indicate:
lRoad speed.
lEngine speed.
lFuel tank level.
lEngine coolant temperature.
The dials are driven by a microprocessor from information received from the serial communication link. Information
input is received as either:
lDigital.
lAnalogue.
lPulse train.
lPulse Width Modulation (PWM).
The LCD provides information for:
lOdometer.
lTrip distance.
lSelected gear (on vehicles fitted with an automatic gearbox).
A trip reset button is provided to zero the trip display, this button also allows the selection of "miles" or "kilometres"
for the display. A photocell controls the illumination of the LCD, maintaining contrast of the display during ambient light
changes.
Within the four warning lamp packs there are 28 lamps. A long life bulb illuminates the high beam warning lamp and
the rest of the warning lamps are illuminated by Light Emitting Diodes (LED's). All warning lamp legends are invisible
until lit. When lit the symbols are illuminated on a black background.
The warning lamps illuminate in one of four colours. The colour indicates the level of importance to the driver, as
follows:
lRed = warning.
lAmber = caution.
lGreen = system operative.
lBlue = main beam operative.
The first warning lamp pack is located in the top left-hand side of the instrument pack and contains the following
warning lamps:
lTraction control warning lamp.
lTransfer box in neutral warning lamp.
lDifferential lock warning lamp
lOverspeed warning lamp (activated for gulf market only).
lBrake system warning lamp.
lHill Descent Control (HDC) information warning lamp.
lMalfunction Indicator Lamp (MIL)/ SERVICE ENGINE SOON warning lamp.
The second warning lamp pack is located in the centre of the instrument pack and contains the following warning
lamps:
lDirection indicator warning lamps.
lHigh beam warning lamp.
lAnti-lock brake system warning lamp.