1999 LAND ROVER DISCOVERY door lock

WIPERS AND WASHERS
84-12 DESCRIPTION AND OPERATION
Rear wiper
The rear wiper is driven directly from an electric motor located inside the tail door. The motor is mounted inside the
tail door with two bolts, lock washers and washers. The motor mounting brackets have rubber inserts to prevent motor
operating noise being transferred to the door structure. The motor spindle is fitted with a seal and protrudes through
a hole in the tail door outer skin panel. The motor spindle is secured to the tail door with a washer and nut.
The motor output spindle has a taper splined shaft which allows for the attachment of the wiper arm which is secured
with a nut. The wiper arm attachment to the splined shaft has a pivot to which the remainder of the arm is attached.
The two parts of the arm are connected by a spring which controls the pressure of the blade on the window to a
predetermined amount.
The wiper blade is attached to the wiper arms with a clip which allows the blade to pivot. The wiper blade comprises
of a number of levers and yokes to which the rubber wiper is attached. The levers and yokes ensure that the pressure
applied by the arm spring is evenly distributed along the full length of the blade. The rubber wiper is held in the yokes
by a pair of stainless steel strips which also contribute to the even distribution of spring pressure along the blade.
Rear wiper switch
The rear wiper switch is a latching pushbutton switch and is located on the right hand side of the instrument pack.
Activating the rear wiper switch provides an earth signal to the BCU. The BCU signals the IDM to energise the rear
wiper relay, which provides battery voltage to the rear wiper motor.

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-1
BODY CONTROL UNIT DESCRIPTION AND OPERAT ION
Description
General
The Body Control Unit (BCU) is located behind the passenger glovebox and is connected to the main harness by four
connectors on its bottom edge and an additional connector located on the side of the BCU casing. Mounting the BCU
behind the fascia makes it reasonably inaccessible for intruders to disable the anti-theft system.
The BCU uses solid-state microprocessor control to perform logical operations and timing functions for a variety of
the vehicle's electrically operated systems, these include:
lDoor locking.
lAnti-theft alarm and immobilisation system.
lExterior lighting including direction indicators and hazard warning lamps.
lCourtesy lighting.
lWipers and washers.
lElectric windows and sunroof.
lHeated windows.
The BCU also communicates with several other electronically controlled systems such as the EAT ECU and SLABS
ECU and also has a datalink between the Intelligent Driver Module (IDM) and the instrument pack. The datalink is a
low speed bus capable of transmitting and receiving messages at a data rate of 10,400 bits per second. Additional
inputs and outputs to peripheral devices are included which are necessary for determining vehicle status for particular
logical operations e.g. crank, ignition key inserted, fuel flap enable etc.
The BCU receives its power supply from the engine compartment fuse box, and is protected by a 10 A fuse.
The BCU communicates with the IDM to provide the control signals to perform power switching operations in
conjunction with dedicated relays.
IDM
The IDM is integrated into the passenger compartment fuse box, which is mounted behind the fascia below the
steering column. There are no harnesses between the fuse box and the IDM. The IDM performs the power switching
operations for several of the vehicle's electrical systems.
The IDM communicates with the BCU and the instrument pack via a serial interface. If the BCU or the IDM is replaced,
the communications link between the two units has to be re-established. This can be done either by switching on the
ignition and leaving it on for five minutes, or by using TestBook. The vehicle immobilisation will remain active until the
communications link between the BCU and IDM has been re-established.
Transit mode
To prevent excessive battery drain during transit to overseas markets, the vehicle is placed in a transit mode. The
following functions are disabled when the vehicle is in transit mode:
lVolumetric sensors.
lPassive immobilisation.
lImmobilisation of the vehicle by use of door lock.
lIgnition key interlock.
lElectric seat enable time-out with driver's door open.

BODY CONTROL UNIT
86-3-2 DESCRIPTION AND OPERATION
Power supply
Battery supply to the BCU and the IDM is provided through a 10 A fuse located in the engine compartment fuse box.
The BCU unit receives an ignition switched power supply (ignition switch position II) input via a 10 A fuse in the
passenger compartment fuse box.
The BCU receives a signal when the ignition switch is turned to the crank position, it then supplies an earth path to
the starter relay coil, to enable the crank operation by supplying power through the starter relay contacts to the starter
motor.
Battery voltage is monitored and BCU operation will function normally between 8 and 18 volts. Between 5.7 and 8
volts the BCU is in the 'under volts' state. The status of the battery is used to determine which outputs may be driven.
If a voltage supply above 18 volts is experienced, outputs will not normally be driven except for those functions which
are required during cranking (robust immobilisation, antenna coil, crank enable relay and feed to gear position switch
contacts W, X, Y, Z). In the over voltage state the vehicle can be driven, but all other functions are disabled and
outputs are switched off (power windows, heated screen, direction indicators etc.).
All functions are disabled on power up until communications between the BCU and IDM have been established. If
communications cannot be established, operation will commence with degraded functionality.
Battery supply to the IDM is provided through the inertia switch and a 10 A fuse in the engine compartment fuse box.
If the inertia switch contacts are closed battery voltage is available at the IDM; if the inertia switch contacts are open
there is no battery supply to the IDM. The supply condition of the IDM is signalled to the BCU via the serial bus. If the
inertia switch is operated (contacts open) the change in state is detected by the BCU which unlocks the doors if the
ignition switch is in position II and the alarm is not set.
The BCU is earthed through a hard-wire connection.
Inputs and outputs
The BCU and IDM process inputs and provide the necessary outputs for control and operation of the vehicle's 'body'
systems.
BCU inputs
The BCU processes signals received from the following components:
lDoor latch switches.
lDriver's door key lock/ unlock switches.
lBonnet activated security system.
lVolumetric sensors.
lCentral Door Locking (CDL) switches.
lRemote transmitter (via receiver unit).
lInertia fuel cut-off switch.
lIgnition switch.
lFuel flap release switch.
The input voltages (V
in) for BCU digital signals are defined as follows:
lLogic 1 when V
in ≥ 6V.
lLogic 0 when V
in ≤ 2V.
BCU input voltages between 2 and 6 volts are indeterminate and cannot be guaranteed.
Analogue input voltages are measured as a ratio with respect to battery voltage.

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-3
BCU outputs
The BCU processes the input signals it receives and uses the information to determine the control outputs that need
to be established for any given set of conditions. The BCU provides controlled outputs for the following systems:
lInterior courtesy lamps.
lFuel flap release actuator.
lAnti-theft status LED.
lEngine Control Module.
lDoor lock actuators.
lDirection indicators and hazard warning lamps.
lHeadlamps.
lAlarm sounder.
lVehicle horns.
lBattery backed sounder.
lStarter relay.
lPassive re-mobilisation exciter coil.
Simultaneous switching of outputs in different units is limited by the bus transfer time, but the skew is no longer than
100 ms for either the BCU or the IDM. When the processor is reset, all outputs are switched off until the inputs have
been read for the first time to check current condition.
BCU to harness connectors
1Connector C0661
2Connector C0662
3Connector C06634Connector C0660
5Connector C0664
The pinout details for the BCU connectors are defined below:

BODY CONTROL UNIT
86-3-4 DESCRIPTION AND OPERATION
C0660 connector pin details
Pin No. Description Input/Output
1 Ignition power supply Input
2 Right front window - down Input
3 Auxiliary power supply Input
4 Passenger or rear door open Input
5 Driver's door key lock Input
6 RH indicator selected Input
7 Front fog lamps selected Input
8 Gear position feedback 'R' Output
9 Gear position feedback 'P' Output
10 SLS too high (audible warning) Input
11 Earth -
12 Vehicle raise/lower request Output
13 Battery power supply Input
14 Heated front screen selected Input
15 Bonnet open Input
16 CDL doors lock Input
17 Driver's door open Input
18 Left front window up Input
19 Right front window up Input
20 Rear washer pump Input
21 Front intermittent wiper switch Input
22 Gear position feedback '1' Output
23 Gear position feedback '2' Output
24 Gear position feedback '3' Output
25 Gear position feedback 'D' Output
26 Gear position feedback 'N' Output

BODY CONTROL UNIT
DESCRIPTION AND OPERATION 86-3-5
C0661 connector pin details
Pin No. Description Input/Output
1 Serial bus to instrument pack and IDM Input/Output
2 Not used -
3 Battery backed up sounder code (AL) Output
4 Diagnostic bi-directional 'K'-line Input/Output
5 RF regulated power supply Output
6 RF receiver input Input
7 Brake switch activated Input
8 Reverse gear selected Input
9 Sunroof enable line Output
10 Robust immobilisation Output
11 Front washer pump Input
12 Heated front screen relay Output
13 Heated front screen active Output
14 Battery backed up sounder code (ST) Output
15 Heated rear screen active Output
16 'N' or 'R' or 'P' or brake selected Output
17 Not used -
18 Passive remobilisation exciter coil Output
19 RF battery supply from fuse 20 in passenger compartment
fuseboxInput
20 Security status LED Output
21 Front intermittent wiper Input
22 Driver's door key unlock Input

BODY CONTROL UNIT
86-3-6 DESCRIPTION AND OPERATION
C0662 connector pin details
Pin No. Description Input/Output
1 Front left window - down Input
2 Ignition key inserted Input
3 Rear wiper Input
4 Vehicle horns Input
5 Crank enable Output
6 Gear position switch (Y contacts) Input
7 CDL doors unlock Input
8 Rear fog lamps selected Input
9 Gear position switch (W contacts) Input
10 Drive selected (HDC) Output
11 Ignition key interlock solenoid Output
12 Headlamp powerwash Output
13 Gear position switch (X contacts) Input
14 Not used -
15 Transfer box - neutral selected Input
16 Seat buckle fastened Input

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