2002 LAND ROVER DISCOVERY battery

INSTRUMENTS
DESCRIPTION AND OPERATION 88-17
Main beam warning lamp
The main beam warning lamp within the instrument pack utilises a clear 14 volt 2 watt long life bulb and a blue legend.
The bulb illuminates when the headlamps are switched to main beam, providing the driver with a visible warning.
There is no self-test performed at ignition on for this warning lamp.
Operating the main beam switch provides the Intelligent Driver Module (IDM) with battery voltage. This feed activates
the IDM to supply the power for the main beam warning lamp. The earth path is provided through the instrument pack.

INSTRUMENTS
88-30 DESCRIPTION AND OPERATION
Water sensor
On vehicles with diesel engines a water sensor is located in the bottom of the fuel filter. The sensor utilises the
different resistance properties between water and diesel fuel to determines the presence of water in the fuel.
The sensor receives a battery voltage supply from the fuel pump relay. The sensor output is supplied to the instrument
pack. The water sensor provides the earth path to illuminate the warning lamp.
l< 1.8 volts = warning lamp on.
l> 7.7 volts = warning lamp off.

INSTRUMENTS
88-36 DESCRIPTION AND OPERATION
Self Levelling Suspension (SLS) warning lamp
The SLS warning lamp within the instrument pack utilises an amber LED and a clear legend. The SLABS ECU
illuminates the LED continuously if a fault within the SLS is detected, providing the driver with a visible warning.
When the ignition is switched on the SLABS ECU illuminates the LED to provide a self-check, providing there is no
fault it will remain illuminated for 3 seconds or until the ignition is switched off.
On vehicles equipped with coil springs the SLS warning lamp is extinguished after 850 milliseconds if the SLABS ECU
configuration of the vehicle is correct.
The SLS warning lamp flashes at 2 Hz when the remote handset control is used to raise or lower the ride height.
If a new SLABS ECU is installed the SLS warning lamp will remain illuminated until the ECU has been calibrated by
TestBook.
The warning lamp will illuminate continuously when battery voltage is less than 10 volts for greater than 1 second.
When the vehicle is in transportation mode the SLS warning lamp is illuminated continuously with ignition on, and will
flash at 2 Hz frequency as the vehicle rises from bump stop level to transport level on engine start.
The power input for the LED is supplied by the instrument pack via fuse 27. The SLABS ECU provides the earth path
to illuminate the warning lamp.
The voltage on the earth path from the SLABS ECU to the instrument pack has the following functions:
l< 1.8 volts = warning lamp on.
l> 7.7 volts = warning lamp off.

INSTRUMENTS
88-42 DESCRIPTION AND OPERATION
Interior rear view mirror with compass
(where fitted)
1Cover
2Electrical connector
3Mounting bracket
4Light sensor
5Compass 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
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