engine LAND ROVER DEFENDER 1996 Workshop Manual

AIR CONDITIONING
13
REPAIR HEATER/COOLER UNIT - RH DRIVE
Service repair no - 82.25.21
Remove
1.Disconnect battery.
2.Recover refrigerant from air conditioning system
See Refrigerant recovery, recycling,
recharging.
3.Release ties, remove insulation cover and
disconnect evaporator low pressure pipe.
4.Disconnect evaporator high pressure pipe.
5.Discard all pipe connection 'O' rings. Cap or plug
all connections to prevent ingress of dirt and
moisture.
6.Using suitable pipe clamps, clamp heater matrix
feed and return pipes at heater/cooler unit.
7.Remove screw securing air control flap solenoid.
8.Disconnect 2 leads from thermostat.
9.Remove pipe from water valve vacuum switch.
10.Remove retaining clip and disconnect control
cable from evaporator flap operating rod.
11.Remove screw and release outer cable retaining
bracket.12.Disconnect blower motor wiring plugs and
release harness retaining clip from housing.
13.Remove bolt securing front support bracket to
blower motor housing. If necessary, remove
blower motor resistor block to facilitate
operation.
14.From inside vehicle remove front passenger
carpet, if fitted.
15.Remove fixing screws and fold back footwell
insulation.
16.Remove 4 bolts securing heater/cooler unit lower
mounting bracket to bulkhead. Ensure spacing
washers from two innermost bolts are retrieved
from engine bulkhead side.
17.From inside engine compartment remove 2 bolts
securing top heater/cooler unit mounting bracket
to engine bullkhead.
18.Lift heater/cooler unit clear of air duct seal and
remove from vehicle.

82AIR CONDITIONING
14
REPAIR Refit
19.Coat unions, threads and new 'O' rings with
refrigerant oil prior to reassembly.
20.Position heater/cooler unit in engine
compartment and locate with air duct seal.
21.Secure unit top and bottom mounting brackets to
bulkhead and support bracket to front of unit
casing. Fully tighten fixing bolts when unit is
correctly positioned.
22.If applicable, fit blower motor resistor block to
vehicle wing.
23.Connect blower motor wiring plugs.
24.Fit footwell insulation and carpet.
25.Fit control cable to evaporator flap operating rod
using new clip. Secure outer cable.
26.Connect water valve vacuum switch pipe and
thermostat leads.
27.Fit air control flap solenoid to side of
heater/cooler unit.
28.Reconnect heater matrix hoses.
29.Connect high pressure pipe to evaporator.
30.Connect low pressure pipe and fit insulation
cover.
31.Evacuate and recharge air conditioning system
See Adjustment, Refrigerant recovery,
recycling, recharging.
32.Reconnect battery.

AIR CONDITIONING
15
REPAIR EVAPORATOR - RH DRIVE
Service repair no - 82.25.20
Remove
1.Remove heater/cooler unit
See Heater/cooler
unit - RH drive.
2.Suitably support unit on a bench.
3.Remove sealant and release thermostat probe
from low pressure pipe.
4.Remove 2 screws securing blower motor cover
to main casing.
5.Withdraw cover sufficiently to release motor
Lucar connector and earth eyelet. Remove
cover.
6.Unscrew top adaptor pipe from heater matrix.
7.Remove 18 fixings securing top cover to main
casing and heater/cooler support frame.
8.Carefully break sealing compound around edge
of joint seam and remove top cover from main
casing.
9.Lift out heater matrix.
10.Remove 2 screws securing back of evaporator
to support frame.
11.From underneath, remove 2 nuts and washers
securing evaporator matrix to base of casing.
12.Lift evaporator matrix from casing, complete with
side plates.
13.Remove side plates
14.Clean sealing compound from all joint seams of
main casing and top cover.
NOTE: The evaporator matrix is supplied
complete with the expansion valve.
However, a faulty expansion valve can be
serviced separately,
See Expansion valve - RH
drive.
Refit
15.Locate side panels to new evaporator lower
fixing studs.
16.Fit evaporator, with side plates, into main casing.
Ensure both studs are located through bottom of
casing and secure.
17.Apply sealing compound around joint seam of
main casing.
18.Fit top cover to main casing.
19.Fit thermostat probe to to low pressure pipe and
apply sealant.
20.Fit top adaptor pipe to heater matrix.
21.Fit Lucar connector and eath eyelet to blower
motor.
22.Fit blower motor cover.
23.Fit heater/cooler unit assembly into engine
compartment
See Heater/cooler unit.

AIR CONDITIONING
17
REPAIR HEATER MATRIX - RH DRIVE
Service repair no - 82.25.19
Remove
1.Remove heater/cooler unit
See Heater/cooler
unit - RH drive.
2.Suitably support unit on a bench.
3.Remove sealant and release thermostat probe
from low pressure pipe.
4.Remove 2 screws securing blower motor cover
to main casing.
5.Withdraw cover sufficiently to release motor
Lucar connector and earth eyelet. Remove
cover.
6.Unscrew top adaptor pipe from heater matrix.
7.Remove 18 fixings securing top cover to main
casing and heater/cooler support frame.
8.Carefully break sealing compound around edge
of joint seam and remove top cover from main
casing.
9.Lift out heater matrix.
10.Clean sealing compound from all joint seams of
main casing and top cover.
Refit
11.Locate heater matrix in main casing.
12.Apply sealing compound around joint seam of
main casing.
13.Fit top cover to main casing.
14.Fit adaptor pipe to heater matrix.
15.Fit thermostat probe to to low pressure pipe and
apply sealant.
16.Fit Lucar connector and eath eyelet to blower
motor.
17.Fit blower motor cover.
18.Fit heater/cooler unit assembly into engine
compartment
See Heater/cooler unit.

ELECTRICAL
1
DESCRIPTION AND OPERATION ELECTRICAL EQUIPMENT
Description
The electrical system is Negative ground, and it is
most important to ensure correct polarity of electrical
connections at all times. Any incorrect connections
made when reconnecting cables may cause
irreparable damage to semi-conductor devices used in
generator and regulator. Incorrect polarity would also
seriously damage any transistorized equipment such
as a radio.
WARNING: During battery removal or
before carrying out any repairs or
maintenance to electrical components
always disconnect battery negative lead first. If
positive lead is disconnected with negative lead in
place, accidental contact of wrench to any
grounded metal part could cause a severe spark,
possibly resulting in personal injury. Upon
installation of battery positive lead should be
connected first.
GENERATOR
The generator is a three phase, field sensed unit. The
rotor and stator windings produce three phase
alternating current, AC, which is rectified to direct
current, DC. The electronic voltage regulator unit
controls generator output voltage by high frequency
switching of the rotor field circuit. Use only correct
replacement drive belt. Occasionally check that
engine and generator pulleys are accurately aligned.
It is essential that good electrical connections are
maintained at all times. Of particular importance are
those in the charging circuit (including those at
battery) which should be occasionally inspected to
see that they are clean and tight. In this way any
significant increase in circuit resistance can be
prevented.Do not disconnect battery cables while engine is
running or damage to semi-conductor devices may
occur. It is also inadvisable to break or make any
connections in the generator charging and control
circuits while engine is running.
The electronic voltage regulator employs micro-circuit
techniques resulting in improved performance under
difficult service conditions. The whole assembly is
encapsulated in silicone rubber and housed in an
aluminium heat sink, ensuring complete protection
against adverse effects of temperature, dust, and
moisture etc.
The regulating voltage is set during manufacture to
give required regulating voltage range of 14.2±0.2
volts, and no adjustment is necessary. The only
maintenance needed is occasional check on terminal
connections and wiping with a clean dry cloth.
The generator system provides for direct connection
of a charge (ignition) indicator warning lamp, and
eliminates the need for a field switching relay or
warning light control unit. In the event of bulb failure,
an 'exciter' voltage is supplied through a resistor,
wired in parallel to the bulbs, ensuring that generator
output is maintained. The lamp should be checked
regularly.
When using rapid charge equipment to re-charge
battery, the battery must be disconnected from the
vehicle.

86ELECTRICAL
2
DESCRIPTION AND OPERATION VEHICLE IMMOBILISATION AND ALARM SYSTEM
A sophisticated engine immobilisation and anti-theft
alarm system is offered on the Land Rover Defender
300 Tdi vehicle range, which incorporates the
following features:
Perimeter protection
This part of the alarm system protects side doors,
bonnet and rear door against unauthorised entry -
alarm sounding if any one of these apertures is
opened without alarm first being disarmed.
Interior protection
Also known as volumetric protection, this part of the
system protects space inside the vehicle. Once
armed, the alarm will sound if a door is opened, or if
movement is detected inside the vehicle.
Engine immobilisation
The engine is immobilised electronically whenever the
alarm system is armed. Even if the alarm has not
been armed, engine immobilisation will occur
automatically thirty seconds after the driver's door is
opened, or five minutes after the starter switch is
turned to position '0'.
ALARM SYSTEM COMPONENTS
Electronic control unit (ECU)
The ECU is the alarm system brain and controls all
vehicle immobilisation and alarm functions. It
responds to the inputs received, by supplying suitable
outputs to indicate status of the alarm system or
activating relevant warning devices. unit is located
under fascia behind instrument binnacle.
Handset and key
The handset is the primary source of control for the
alarm system i.e. it arms and disarms the alarm
components. The key can be used to override engine
immoblisation if the handset is lost or fails to operate,
seeEngine immobilisation override.The handset battery should last for approximately
three years dependent upon use. The following
symptoms will be noticed when the battery requires
replacement:
1.The handset will only work every other operation
while disarming.
2.The direction indicator lamps will not flash when
the alarm is disarmed.
For battery replacement procedure, seeHandset
Battery.
Passive coil
The passive coil is fitted on the starter switch and
activates a receiving coil in the handset, causing it to
automatically transmit a remobilisation signal to the
ECU.
Aerial
The aerial is integral within the alarm system harness
and supplies the ECU with the signal received from
handset.
Immobilisation spider
The immobilisation spider provides an interface
between ECU and immobilised areas of the vehicle.
This is installed in a sealed (safe) box inside the
vehicle battery box.
Digital diesel shut-off valve - 97 MY
When fitted, the digital diesel shut-off valve
immobilises the fuel injection pump by preventing
power reaching the fuel shut-off solenoid,
See
Immobilisation and alarm system circuit diagram -
with DDS
.

ELECTRICAL
3
DESCRIPTION AND OPERATION Door and bonnet switches
Perimetric protection for the vehicle is provided by
ECU inputs connected to the starter switch, bonnet
switch and door switches.
Ultrasonic sensor
The ultrasonic sensor operates by emitting an air
pressure carrier wave which is subsequently received
by the sensor as it bounces back from objects inside
the vehicle. Once armed, the alarm will sound if wave
is disturbed by a door opening, or if movement is
detected inside the vehicle.
When the volumetric sensor is activated it monitors
movement within the vehicle for 15 seconds before
detecting and responding to intrusions. If the sensor
detects movement it delays arming until a quiet period
has lapsed; if continuous movement is detected, the
alarm will not arm volumetrically.
NOTE: Interior protection will not operate
until 15 seconds after alarm is set.
The ultrasonic sensor is positioned in a different
location, according to vehicle type, as follows:
·90/110 Station Wagon - RH cantrail trim
·90/110 Pick-up - On headlining, between interior
lamp and rear view mirror
·130 Crewcab - On headlining above RH door
Alarm sounder
Two types of alarm sounder can be fitted, one with a
battery back-up facility and or without battery back-up,
both providing an audible warning whenever the alarm
is triggered. The vehicle horn will also operate if the
alarm sounds.
The alarm sounder is fitted to LH inner front wing in
the engine compartment.
NOTE: Disconnecting the battery on
vehicles fitted with the battery backed-up
facility will result in the alarm sounding, if
correct procedure has not been followed.Engine immobilisation warning light
The engine immobilisation warning light is located on
the instrument panel, and provides a visual indication
that the engine is immobilised.
Anti-theft alarm indicator light
The anti-theft alarm indicator light is located on the
instrument panel, between the fuel and coolant
temperature indicators, and provides a visual
indication of the alarm/ immobiliser status.

86ELECTRICAL
4
DESCRIPTION AND OPERATION REV: 05/99 ALARM SYSTEM COMPONENT LOCATION
COMPONENT LOCATION
1. Electronic control unit (ECU) Under dash, LH and RH drive
2. Anti-theft alarm indicator light Instrument panel
3. Engine immobilisation warning light Instrument panel
4. Immobilisation spider* Inside vehicle battery box
5. Passive coil Over starter switch barrel
6. Bonnet switch Engine compartment, LH and RH drive
7. Door switches
8. Ultrasonic sensor Varies according to vehicle type
9. Handset and key
10. Alarm sounder (without battery back-up) LH inner front wing
11. Alarm sounder (with battery back-up) LH inner front wing
* Replaced in some markets by a digital diesel shut-off valve (DDS), secured directly to fuel shut-off solenoid on
injection pump.

ELECTRICAL
5
DESCRIPTION AND OPERATION REV: 05/99 ALARM SYSTEM OPERATION
Arming alarm
To arm the alarm, aim handset at vehicle and press
the RH button (Padlock symbol). Provided all doors
and or apertures are closed, the direction indicator
lamps will flash three times to confirm that the alarm is
armed. All security features previously described will
be active.
Once armed, the alarm will sound if a door or the
bonnet is opened, or if movement is detected inside
the vehicle.
Disarming alarm
Within range of the vehicle, briefly press the LH
(Plain) button on the handset; the direction indicator
lamps will flash once to indicate that the alarm has
been disarmed and the engine re-mobilised.
NOTE: In some territories, the interior
lamps will illuminate when the alarm is
disarmed.
If the direction indicators fail to flash when the
alarm is armed:
This indicates that a door or the bonnet is not fully
closed, in which case the alarm will be partially armed
and engine immobilised, but interior protection will not
be active.
Once the open door or bonnet is closed, the direction
indicators will flash three times and the alarm will fully
arm as described previously.
If the alarm sounds:
The vehicle horn and alarm sounder will operate
continuously for 30 seconds when the alarm is
triggered. The horn and alarm sounder can be
triggered up to three times.
To silence the alarm, press either handset button. If
the handset is inoperative, the alarm can only be
disarmed by entering the emergency key access
code, seeEngine immobilisation override.Anti-theft alarm indicator light
A RED indicator light on the instrument panel
indicates the status of the alarm system. When the
alarm is armed successfully, the light flashes rapidly.
After 10 seconds, the light adjusts to a slower
frequency and continues flashing as an anti-theft
deterrent.
If the light fails to illuminate during the rapid flash
phase, this indicates a 'mislock' (door or the bonnet
not fully closed or key in starter switch). If this occurs,
the indicator light will still flash at slower frequency as
an anti-theft deterrent.
The indicator light will illuminate continuously under
the following conditions:
1.Alarm system armed and immobilised with
ignition 'on' or driver's door open.
2.Engine immobilised with ignition 'on' or driver's
door open.
Interior protection
Interior protection is activated automatically when the
alarm system is armed; twin sensors inside the
vehicle monitor interior space and will activate the
alarm if an intrusion is detected.
However, if passengers or animals are to be left inside
the vehicle, or if a window or sunroof is to be left
open, the alarm must be armed with the interior
protection DISABLED as follows:
To disable interior protection:
1.Open the driver's door.
2.Use the handset to arm the alarm in normal way.
3.Close the driver's door (the direction indicator
lamps will flash three times and the anti-theft
indicator light commences flashing rapidly). The
alarm system is now armed with the interior
protection disabled.
NOTE: Interior protection will not operate
until 15 seconds after the alarm is set.

86ELECTRICAL
6
DESCRIPTION AND OPERATION REV: 05/99 ENGINE IMMOBILISATION
Engine immobilisation is an important aspect of the
vehicle's security system, and occurs automatically
whenever the alarm system is armed.
The system also includes a feature known as 'passive
immobilisation', which is designed to safeguard the
vehicle from theft should the driver forget to arm the
alarm.
Passive immobilisation occurs automatically as
follows:
·Thirty seconds after the starter switch has been
turned off and the driver's door opened.
·Five minutes after the starter switch is turned off or
the alarm system is disarmed.
If the engine has immobilised passively,
re-mobilisation will occur when the starter switch is
turned to position 'II', provided the handset is on the
same ring as key and in close proximity to the switch.
ALWAYS keep the handset on the same ring as the
key.
NEVER attach both handsets to the same key ring.
Any attempt to start the engine while it is immobilised
will cause the engine immobilisation warning light to
flash.
Engine immobilisation override
If the handset is lost or fails to operate, the engine
immobilisation can be overridden by using the starter
key to enter the four digit emergency access code.
The procedure for entering the code is described after
the following note:
NOTE: If the handset is lost or inoperative,
it is impossible to disarm the alarm. As
soon as the door is opened, the alarm will
sound (continuously for up to three 30 second
periods), and continue while the code is being
entered.
1.With the driver's door closed, insert the key into
the starter switch.
2.Turn the switch to position 'II' the required
number of times to enter first digit of code (if first
digit is 4, turn key to position 'II' and then back to
'0' four times.
3.Open the driver's door (to enter first digit) and
then close the door again.
4.Turn the starter switch to position 'II' and back to
'0' the required number of times to enter
SECOND digit of code.
5.Open the driver's door (to enter second digit)
and then close the door again.
6.Turn the starter switch to position 'II' and back to
'0' the required number of times to enter THIRD
digit of code.
7.Open the driver's door (to enter third digit) and
then close door again.
8.Turn the starter switch to position 'II' and back to
'0' the required number of times to enter
FOURTH digit of code.
9.Finally, open and close the driver's door. If the
code has been entered correctly, the anti-theft
indicator light will extinguish, the engine can be
started and the alarm will disarm.
If an incorrect code has been entered:
If the code is entered incorrectly, the anti-theft
indicator light will continue to illuminate and the
engine will fail to start. Before entering the code again,
turn the starter switch to position 'II', hold in this
position for 5 seconds and then switch off.
After three failed attempts, the security system
invokes a delay period of thirty minutes during which
the system will not accept any further codes.