1999 LAND ROVER DISCOVERY Workshop Manual

INSTRUMENTS
88-38 DESCRIPTION AND OPERATION
Gearbox manual/sport mode warning lamps
The gearbox manual/sport mode warning lamps within the instrument pack each utilise a green LED and a clear
legend. On vehicles fitted with an automatic gearbox, operating the manual mode switch instructs the Electronic
Automatic Transmission (EAT) ECU to illuminate the manual mode LED. Operating the sport mode switch instructs
the EAT ECU to illuminate the sport mode LED.
There is no self-test performed at ignition on for this warning lamp.
If the EAT ECU detects a fault it will cause both warning lamps to flash.
The power input for the LED's is supplied by the instrument pack. The EAT ECU applies a high or low voltage to the
instrument pack microprocessor which measures the applied voltage from the ECU and illuminates the appropriate
warning lamp.
The voltage on the earth paths from the EAT ECU to the instrument pack has the following functions:
Warning lamp response Manual earth path, volts Sport earth path, volts
No lamps > 7.7 > 7.7
Sport warning > 7.7 < 1.8
Manual warning < 1.8 > 7.7
Both lamps flash < 1.8 < 1.8

INSTRUMENTS
DESCRIPTION AND OPERATION 88-39
Anti-theft status warning lamp
The anti-theft status warning lamp within the instrument pack utilises a red LED and a clear legend.
The BCU illuminates the LED when the vehicle anti-theft system is active.
This provides a warning to potential thieves that the vehicle is protected by a security system.
When the ignition is switched on, the ECM illuminates the LED to provide a self-check, providing there is no fault it
will remain illuminated until the engine is started or the ignition is switched off.
The power input for the LED is supplied by the instrument pack via fuse 13. The BCU controls the earth path to
illuminate the warning lamp.
The voltage on the earth path from the BCU to the instrument pack will be less than 1 volt when the anti-theft status
is enabled.

INSTRUMENTS
88-40 DESCRIPTION AND OPERATION
Audible warning speaker
The audible warning speaker is integral with the instrument pack and provides an audible warning to alert the driver
of the following situations:
lSeat belt warning lamp.
lKey in/lights on warning.
lSLABS command received warning.
lTransfer box in neutral warning.
lLights on warning.
It has a maximum pressure level of 87 dB at 1 metre (3.3 ft). The audible warning speaker is located on the rear of
the instrument pack.
The power input for the audible warning speaker is supplied by the instrument pack via fuse 27.
The BCU provides the earth paths for the following:
lThe seatbelt warning.
lKey in/lights on warning.
lLights on warning.
The SLABS ECU provides the earth paths for the SLABS commands. The EAT ECU provides the earth path for the
transfer box in neutral warning.
The BCU activates the audible warning speaker to produce audible warnings.
The audible warning speaker can operate with the ignition off.
The seatbelt warning will commence at key on, and in the event of a serial link failure, will terminate after 6 seconds.
The SLABS warnings are sounded only once for each received command.
The lights on warning and transfer box in neutral are sounded continuously until a sound off command is received.
Sound request number Sound functions Priority (1 = lowest, 6 = highest)
0Off 1
1 Seat belt warning 6
2Key-in warning 3
3 SLABS/ HDC warning 4
4 Transfer box in neutral warning 5
5 Lights on warning 2

INSTRUMENTS
DESCRIPTION AND OPERATION 88-41
Diagnostic connector
RHD illustrated
The diagnostic connector allows TestBook to communicate with the vehicle electrical system.
The modules that TestBook can interface with via the diagnostic connector are:
lSLABS ECU.
lBCU.
lECM (V8 and Td5).
lIDM.
lACE ECU.
lEAT ECU.
lSRS DCU.
TestBook communicates with the ECM, ECU's and the instrument pack for diagnostic purposes and for configuration
for a specific options or market. If communications on the diagnostic connector fail for greater than three seconds after
the ignition is in position II the gear selected display in the LCD flashes. This applies to both manual and automatic
vehicles in all markets.
The instrument pack options configured by TestBook are:
lAutomatic or manual gearbox fitted.
lDiesel or V8 engine fitted.
lACE fitted.
lSLS fitted.
lGulf, Japan or ROW markets.
lService engine reset.
lOdometer reset.
lHDC fitted.
lTraction control fitted.
The serial communications link is a bi-directional communications network providing both input and output on the
same pin.
M86 4705

INSTRUMENTS
88-42 DESCRIPTION AND OPERATION
Interior rear view mirror with compass
(where fitted)
1Cover
2Electrical connector
3Mounting bracket
4Light sensor5Compass LED display
6Compass calibration switch
7Compass printed circuit board
Certain vehicles have an interior rear view mirror that features an automatic photochromatic dimming function and an
electronic compass with LED display.
The compass mirror is a self-contained unit and does not interface with any other vehicle system or electronic control
unit. The mirror is fixed to a metal bracket attached to the windscreen.
A three pin connector provides the electrical connection to the mirror's internal circuit board. Pin-1 of the connector
provides the 12V power supply to the board via the auxiliary relay located in the engine compartment fusebox. When
the ignition switch is turned to the 'II' position, a 12V supply is provided to energise the coil of the auxiliary relay via
fuse 26 in the passenger compartment fusebox. The auxiliary relay's contact supply voltage is provided from the
vehicle battery through fusible links 1 & 7. When the relay's contacts close, a 12V supply is fed to the compass mirror
circuit board via fuse 15 in the passenger compartment fusebox. This is the supply voltage feed for the mirror's internal
compass.
Pin-2 of the electrical connector provides the path to earth.
Pin-3 of the electrical connector is a 12V ignition switched supply voltage (position 'II' of the ignition switch). The
supply voltage is provided to the mirror's circuit board via fuse 25 in the passenger compartment fusebox, and the
reverse lamp switch (normally closed) for vehicles with manual transmission or the starter inhibitor / reverse light
switch (normally closed) for vehicles with automatic transmission. This is the supply voltage feed for the mirror's
photochromatic dimming function.
M88 0297
3
2
7
616
45

INSTRUMENTS
DESCRIPTION AND OPERATION 88-43
Compass
The mirror's compass display is activated when the ignition switch is turned to position 'II'. If the compass has been
previously calibrated, the current direction of the vehicle will be shown in the LED display at the upper RH side of the
mirror's reflective surface. The display is able to indicate one of eight compass points (i.e. N, NE, E, SE, S, SW, W or
NW).
The compass mirror circuit board contains a microchip which is able to determine changes in vehicle direction due to
the changes in the earth's magnetic field. The circuit board is located in the stem of the mirror so that it follows the
changes in the vehicles direction and is not affected by adjustment of the mirror itself.
Because of changes in the lines of magnetic influence, the compass is set for operation in one of fifteen different zones
depending on the current location of the vehicle. If the vehicle is to be driven in a different zone, the compass will have
to be reset for operation in that zone. To determine the correct zone for a particular location on the planet, refer
to the maps provided in the Owner's Handbook. The mirror's default setting is zone 8 which is suitable for central
European countries (Germany, Austria, Italy etc.).
The compass should be set to the correct zone using the following procedure:
1Switch the ignition to position 'II'.
aIf the compass displays one of the eight compass point directions, proceed to step '3'.
bIf the compass displays 'C' then proceed to step '2'.
cIf the display does not show either of the above, then the calibration button on the underside of the mirror
should be pressed and held for approximately 6 seconds, using a small probe (e.g. paper clip or ballpoint
pen). The compass should now enter the set mode and 'C' should be shown in the display.
2To calibrate the compass, the vehicle must be driven slowly (5 mph (8 km/h) or less) in a circle until the display
shows a direction (usually 1 or 2 revolutions). The mirror can calibrate itself during normal driving, but this will
take considerably longer.
3Set the compass to the relevant zone of magnetic influence by pressing the calibration button on the underside
of the mirror for approximately 3 seconds, using a small probe, until a number is shown in the display. If the zone
is being entered for the first time, the default zone setting '8' should be displayed. If the zone is being reset from
a previous entry, the previous zone setting number will be displayed.
The calibration button should now be pressed and released with single presses, using a small probe, until the
desired zone number appears in the display.
After approximately 10 seconds, the compass display should return correctly set to the required zone.
Note the degree of magnetic variation from one zone to another is only very slight. Recalibration of the compass is
not normally necessary unless several zone changes are undertaken.
Automatic dimming
The mirror's automatic dimming function operates when the ignition switch is turned to the 'II' position.
A light sensor is contained at the upper centre of the mirror which detects the intensity of light from the headlights of
following vehicles in dark or low light conditions. When the light intensity is sufficiently high, the mirror automatically
adjusts the brightness of the reflected light by photochromatically changing the mirror's reflective properties and so
preventing glare affecting the driver.
When reverse gear is selected, the power supply for the mirror's photochromatic function is opened so that the mirror
defaults to its normal reflective properties while the reversing operation is in progress.
Another light sensor is located on the rear of the mirror so that the unit can detect the difference between strong
ambient light and that attributable to following vehicle headlights. To check operation of the light dimming function of
the mirror, use the following procedure:
1Turn ignition switch to position 'II', and ensure reverse gear is not selected.
2Cover the sensor on the back of the mirror.
3Shine a bright light on the front (reflective side) of the mirror; the mirror should darken.

INSTRUMENTS
REPAIRS 88-45
REPAIRS
Clock
$% 88.15.07
Remove
1.Carefully remove clock assembly from fascia.
2.Disconnect multiplugs from clock and door
locking switches.
3.Remove door locking switch from clock
assembly and remove clock assembly.
Refit
1.Fit door lock switch to clock assembly and
connect multiplugs.
2.Position and push to secure clock assembly to
fascia.
Instrument pack
$% 88.30.38
Remove
1.Remove steering column nacelle.

+ STEERING, REPAIRS, Nacelle -
steering column.
2.Remove 2 screws and release instrument cowl
from 2 clips on fascia.
3.Disconnect 7 multiplugs from switches.
4.Remove instrument cowl.
5.Remove 4 screws securing instrument pack to
fascia.
6.Disconnect 2 multiplugs from instrument pack.
7.Remove instrument pack.
Refit
1.Position new instrument pack and connect
multiplugs.
2.Align instrument pack to fascia and secure with
screws.
3.Position instrument cowl and connect
multiplugs to switches.
4.Fit instrument cowl to clips and secure cowl
with screws.
5.Fit steering column nacelle.

+ STEERING, REPAIRS, Nacelle -
steering column.