1996 LAND ROVER DEFENDER engine

82AIR CONDITIONING
6
REPAIR 9.Remove plug connector from resistor.
10.Remove relay from connecting block to gain
access to fixing screw.
11.Remove screw and release relay connector
block. Retain relay in connector block.
12.Remove screw and detach air conditioning 30
amp fuse bracket from resistor. Refit both
resistor retaining screws.
13.Using suitable pipe clamps, clamp heater matrix
feed and return hoses at base of heater/cooler
unit. Release retaining clips and remove hoses.
14.From inside vehicle remove front passenger
carpet, if fitted.
15.Remove retaining screws and fold back footwell
insulation.
16.Remove 2 bolts securing heater/cooler unit lower
mounting bracket to bulkhead.
17.From inside engine compartment remove 2 bolts
securing top heater/cooler unit mounting bracket
to engine bulkhead. This also releases earthing
leads.
18.Remove bolt securing support bracket to front of
heater/cooler casing.19.Lift heater/cooler unit clear of air duct seal and
remove from vehicle.
20.Discard all pipe connection 'O' rings.
Refit
21.Coat unions, threads and new 'O' rings with
refrigerant oil prior to reassembly.
22.Position heater/cooler unit in engine
compartment and locate with air duct seal.
23.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.
24.Fit footwell insulation.
25.Reconnect heater matrix hoses.
26.Fit air conditioning fuse bracket, relay connector
block, relay and resistor plug connector.
27.Fit control cable to evaporator air flap operating
rod, using a new clip.
28.Fit pipe connector to vacuum switch.
29.Connect compressor clutch switch multi-plug.
30.Connect high and low pressure pipes to
evaporator.
31.Fit expansion tank
See COOLING SYSTEM,
Repair, Expansion tank.
32.Evacuate and recharge air conditioning system
See Adjustment, Refrigerant recovery,
recycling, recharging.
33.Reconnect battery.

82AIR CONDITIONING
8
REPAIR
13.Remove all other fixings securing evaporator
and heater matrix support frame to unit casing.
14.Lift evaporator and heater matrices, complete
with support frame assembly, clear of casing.
Retain heater matrix pipe seal pad.
15.Remove 4 screws securing evaporator matrix to
support frame.
16.Withdraw evaporator matrix, complete with
expansion valve, from support frame.
17.Clean sealing compound from all joints of main
casing, top cover and outlet duct.
NOTE: The evaporator matrix is supplied
complete with the expansion valve.
However, a faulty expansion valve can be
serviced separately,
See Expansion valve.
Refit
18.Fit evaporator matrix in support frame.
19.Fit evaporator, heater matrix and support frame
assembly in casing. Ensure studs for lower
mounting bracket are located through bottom of
casing.
20.Apply mastic sealant around heater matrix pipes
to seal pipe apertures in casing. Fit seal pad
over pipes.
21.Fit 3 bottom fixings to secure to secure base of
support frame.
22.Fit all other fixings to secure support frame
assembly.
23.Locate heater matrix insulation pad and cover
plate.
24.Apply sealng compound around top edge of
main casing.
25.Feed blower motor wiring through top cover and
fit grommet.
26.Fit top cover to casing. Ensure thermostat
temperature probe is inserted in top of
evaporator. Apply mastic sealant to air flap
operating rod aperture.
27.Apply sealing compound to joint face of blower
motor outlet duct.
28.Locate duct over blower motor outlet and secure
to casing.
29.Secure lower mounting bracket to retaining studs
on base of main casing.
30.Fit heater/cooler unit assembly in engine
compartment
See Heater/cooler unit.

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
.