LAND ROVER DEFENDER 1996 Workshop Manual

80HEATING AND VENTILATION
8
REPAIR
8.Release lever assembly and disconnect 3
blower motor leads, noting their positions.
9.Pull control cable through bulkhead grommet
and out from instrument panel cowl.
10.Release retaining clip securing outer cable to
lever assembly.
11.Release inner cable from lever peg.
NOTE: If the blower motor switch is faulty
the complete lever assembly will have to
be renewed.
Refit
12.Fit new control cable to lever assembly peg.
13.Fit retaining clip to secure outer cable.
14.Reconnect blower motor leads.
15.Route cable to rear of instrument panel cowl,
along bulkhead and out through grommet into
engine compartment.
16.Fit lever assembly to panel cowl. Ensure screw
spacers are fitted between cowl and lever
assembly.
17.Fit instrument panel to fascia cowl.
18.With lever in closed position, fit control cable to
heater unit flap lever trunnion.
19.Secure outer cable with retaining clip.
20.Secure control cables to engine bulkhead and
heater hoses with retaining clips.
21.Reconnect battery.

AIR CONDITIONING
1
DESCRIPTION AND OPERATION AIR CONDITIONING SYSTEM
Description
Air conditioning is an optional system which provides
fully integrated climate control for the vehicle interior.
The air conditioning system comprises four major
units as follows:- An evaporator matrix and expansion
valve (1), housed in the heater/ cooler unit (3), an
engine mounted compressor (4), a condenser (5),mounted in front of the radiator, and a receiver/drier
(7) located to the right of the condenser.
Ancillary components in the system comprise a blower
motor (2), also housed in the heater/cooler unit, and
condenser cooling fan motors (6), mounted on a
support frame. The four major units are interconnectd
by preformed metal and flexible refrigerant pipes as
illustrated below (RH drive installation shown).
Coolant flow to a heater matrix, housed in the heater
cooler unit, is controlled by a water valve (8) from a
combined air conditioning panel on the vehicle fascia.
1.Evaporator matrix and expansion valve
2.Blower motor
3.Heater/cooler unit
4.Compressor
5.Condenser6.Condenser fan motors
7.Receiver/drier
8.Water valve
9.Heater matrix feed and return hoses

82AIR CONDITIONING
2
DESCRIPTION AND OPERATION Operation
Evaporator unit and expansion valve
High pressure liquid refrigerant is delivered to the
expansion valve which is the controlling device for the
air conditioning system. A severe pressure drop
occurs across the valve and as the refrigerant flows
through the evaporator it picks up heat from the
ambient air, boils and vaporizes. As this change of
state occurs, a large amount of latent heat is
absorbed. The evaporator is therefore cooled and as
a result heat is extracted from the air flowing across
the evaporator. The refrigerant leaves the evaporator,
on its way to the compressor, as a low pressure gas.
An evaporator sensor measures the air temperature at
the evaporator and engages or disengages the
compressor clutch to prevent icing of the air ways.
Compressor
The compressor, a pump specially designed to raise
the pressure of the refrigerant, is mounted on the front
of the engine and is driven by an independent drive
belt from the crankshaft pulley. The compressor draws
vaporized refrigerant from the evaporator. It is
compressed with a resulting rise in temperature and
passed on to the condenser as a hot, high pressure
vapour.
Condenser
The condenser is mounted directly in front of the
radiator and consists of a refrigerant coil mounted in a
series of thin cooling fins to provide the maximum
heat transfer. Air flow across the condenser is induced
by vehicle movement and assisted by two electric fans
attached to the frame of the condenser. The
refrigerant high pressure vapour enters the condenser
inlet on the RH side. As the vapour passes through
the condenser coils the air flow, assisted by the two
fans, carries the latent heat away from the condenser.
This induces a change of state resulting in the
refrigerant condensing into a high pressure warm
liquid. From the condenser, the refrigerant continues
to the receiver/ drier.
Receiver/drier
This component acts as a reservoir and is used to
hold extra refrigerant until it is needed by the
evaporator. The drier within the receiver unit contains
a filter and dessicant (drying material) which absorb
moisture and prevent dessicant dust from being
carried with the refrigerant into the system.AIR CONDITIONING AND HEATER CONTROLS -
LH DRIVE
1. Temperature control
Move the lever upwards (RED) to increase air
temperature, or downwards (BLUE) to reduce air
temperature.
2. Air conditioning switch
Press the switch (indicator lamp illuminates) to
activate the air conditioning. Press again to switch off.
3. Air recirculation control
Move the lever fully upwards to activate air
recirculation. Move the lever fully downwards to
cancel recirculation.
NOTE: Prolonged recirculation may cause
the windows to mist up.
4. Air distribution control
Lever fully up - air to windscreen vents (also provides
some air to the footwell).
Lever midway - air to fascia vents (also provides some
air to the footwell).
Lever fully down - air to footwell vents (also provides
some air to the windscreen).

AIR CONDITIONING
3
DESCRIPTION AND OPERATION 5. Blower motor fan speed control
Move the lever to the right to progressively increase
fan speed.
Location of air vents - LH drive
AIR CONDITIONING AND HEATER CONTROLS -
RH DRIVE
1. Temperature control
Move the lever to the right (RED) to increase air
temperature, or to the left (BLUE) to reduce air
temperature.
2. Air conditioning indicator lamp
Illuminates when the air conditioning system is
operating.3. Air conditioning switch
Press the RH portion of the switch to activate the air
conditioning (indicator lamp illuminates). Press the LH
portion to switch off.
NOTE: Air conditioning should only be
activated when the engine is running.
4. Blower motor fan speed control
Move the lever upwards to progressively increase fan
speed.

82AIR CONDITIONING
4
DESCRIPTION AND OPERATION 5. Air distribution control
Push LH button - air to windscreen vents (also
provides some air to the footwell).
Push middle button - air to fascia vents (also provides
some air to the footwell).
Push RH button - air to footwell vents (also provides
some air to the windscreen).
6. Air recirculation switch
Press the LH portion of the switch to activate air
recirculation. Press the RH portion for fresh air.
NOTE: Prolonged recirculation may cause
the windows to mist up.

AIR CONDITIONING
1
ADJUSTMENT GENERAL PRECAUTIONS
The refrigerant used in the air conditioning system is
HFC (Hydrofluorocarbon) R134a.
WARNING: R134a is a hazardous liquid
and when handled incorrectly can cause
serious injury. Suitable protective clothing
must be worn when carrying out servicing
operations on the air conditioning system.
WARNING: R134a is odourless and
colourless. Do not handle or discharge in
an enclosed area, or in any area where the
vapour or liquid can come in contact with naked
flame or hot metal. R134a is not flammable, but
can form a highly toxic gas.
WARNING: Do not smoke or weld in areas
where R134a is in use. Inhalation of
concentrations of the vapour can cause
dizziness, disorientation. uncoordination,
narcosis, nausea or vomiting.
WARNING: Do not allow fluids other than
R134a or compressor lubricant to enter the
air conditioning system. Spontaneous
combustion may occur.
WARNING: R134a splashed on any part of
the body will cause immediate freezing of
that area. Also refrigerant cylinders and
replenishment trolleys when discharging will
freeze skin to them if contact is made.
WARNING: The refrigerant used in an air
conditioning system must be reclaimed in
accordance with the recommendations
given with a Refrigerant Recovery Recycling
Recharging Station.
NOTE: Suitable protective clothing
comprises: Wrap around safety glasses or
helmet, heatproof gloves, rubber apron or
waterproof overalls and rubber boots.REMEDIAL ACTIONS
1.If liquid R134a strikes the eye, do not rub it.
Gently run large quantities of eyewash over the
eye to raise the temperature. If eyewash is not
available cool, clean water may be used. Cover
eye with clean pad and seek immediate medical
attention.
2.If liquid R134a is splashed on the skin run large
quantities of water over the area as soon as
possible to raise the temperature. Carry out the
same actions if skin comes into contact with
discharging cylinders. Wrap affected parts in
blankets or similar material and seek immediate
medical attention.
3.If suspected of being overcome by inhalation of
R134a vapour seek fresh air. If unconscious
remove to fresh air. Apply artificial respiration
and/or oxygen and seek immediate medical
attention.
NOTE: Due to its low evaporating
temperature of -30°C, R134a should be
handled with care.
WARNING: Do not allow a refrigerant
container to be heated by a direct flame or
to be placed near any heating appliance. A
refrigerant container must not be heated above
50°C.
WARNING: Do not leave a container of
refrigerant without its cap fitted. Do not
transport a container of refrigerant that is
unrestrained, especially in the boot of a car.

82AIR CONDITIONING
2
ADJUSTMENT SERVICING PRECAUTIONS
Care must be taken when handling refrigeration
system components. Units must not be lifted by their
hoses, pipes or capillary lines. Hoses and lines must
not be subjected to any twist or stress. Ensure that
hoses are positioned in their correct run before fully
tightening the couplings, and ensure that all clips and
supports are used. Torque wrenches of the correct
type must be used when tightening refrigerant
connections to the stated value. An additional spanner
must be used to hold the union to prevent twisting of
the pipe.
Before connecting any hose or pipe ensure that
refrigerant oil is applied to the seat of the new '0' ring
but not to the threads.
Check the oil trap for the amount of oil lost.
All protective plugs on components must be left in
place until immediately prior to connection.
The receiver/drier contains desiccant which absorbs
moisture. It must be positively sealed at all times.
CAUTION: Whenever the refrigerant
system is opened, the receiver/drier must
be renewed immediately before evacuating
and recharging the system.
Use alcohol and a clean cloth to clean dirty
connections.
Ensure that all new parts fitted are marked for use
withR134a.
Refrigerant oil
Use the approved refrigerant lubricating oil - Nippon
Denso ND-OIL 8.
CAUTION: Do not use any other type of
refrigerant oil.
Refrigerant oil easily absorbs water and must not be
stored for long periods. Do not pour unused oil back
into the container.
When renewing system components, add the
following quantities of refrigerant oil:
Condenser 40ml..........................................................
Evaporator 80ml..........................................................
Pipe or hose 20ml........................................................
Receiver/drier 20ml......................................................Total quantity of refrigerant oil in system = 140ml
A new compressor is sealed and pressurised with
Nitrogen gas, slowly release the sealing cap, gas
pressure should be heard to release as the seal is
broken.
NOTE: A new compressor should always
have its sealing caps in place and these
must not be removed until immediately
prior to fitting
A new compressor is supplied with an oil fill of 140ml.
A calculated quantity of oil must be drained from a
new compressor before fitting.
To calculate the quantity of oil to be drained:
1.Remove sealing plugs from the OLD
compressor.
2.Invert compressor and gravity drain oil into
measuring cylinder. Rotating the compressor
clutch plate will assist complete draining.
3.Note the quantity of oil drained (Yml).
4.Calculate the quantity (Qml) of oil to be drained
from the NEW compressor using the following
formula:
Xml - (Yml + 20ml) = Qml
Rapid refrigerant discharge
When the air conditioning system is involved in
accident damage and the circuit is punctured, the
refrigerant is discharged rapidly. The rapid discharge
of refrigerant will also result in the loss of most of the
oil from the system. The compressor must be
removed and all the remaining oil in the compressor
drained and refilled as follows:
1.Gravity drain all the oil, assist by rotating the
clutch plate (not the pulley).
2.Refill the compressor with 90ml of new
refrigerant oil.
3.Plug the inlet and outlet ports.
Servicing Equipment
The following equipment is required for full servicing
of the air conditioning system.
Recovery, recycling and charging station
Leak detector
Thermometer +20°C to -60°C
Safety goggles and gloves

AIR CONDITIONING
3
ADJUSTMENT REFRIGERANT RECOVERY, RECYCLING,
RECHARGING
WARNING: The air conditioning system is
charged with a high pressure, potentially
toxic refrigerant. Repairs or servicing must
only be carried out by an operator familiar with
both the vehicle system and the charging and
testing equipment.
All operations must be carried out in a
well-ventilated area away from open flame and
heat sources.
Always wear safety goggles and gloves when
opening refrigerant connections.
WARNING: Wear eye and hand safety
protection. Open connections slowly in
case liquid or pressure is present. Allow to
bleed off slowly.
CAUTION: Overcharging air conditioning
system will cause excessive head
pressure.
An air conditioning portable Refrigerant Recovery
Recycling Recharging Station for use with R134a
refrigerant incorporates all the features necessary to
recover refrigerant R134a from the air conditioning
system, to filter and remove moisture, to evacuate and
recharge with the reclaimed refrigerant. The unit can
also be used for performance testing and air
conditioning system analysis.
The operator must adhere to the equipment
manufacturers' instructions.
Recovery and recycling
1.Connect a Refrigerant Station to the high and
low pressure servicing connections.
2.Operate the refrigerant recovery system
according to the manufacturers instructions.
3.Measure the amount of oil discharged from the
system. Add an equal amount of new refrigerant
oil to compressor before evacuation sequence.
WARNING: Refrigerant must always be
recycled before reuse, to ensure that the
purity of the refrigerant is high enough for
safe use in the air conditioning system. Recycling
should always be carried out with equipment
which is design certified by Underwriter
Laboratory Inc. for compliance with SAE-J1991.
Other equipment may not recycle refrigerant to
the required level of purity.
A R134a Refrigerant Recovery Recycling
Recharging Station must not be used with any
other type of refrigerant.
Refrigerant R134a from domestic and commercial
sources must not be used in motor vehicle air
conditioning systems.
Evacuation and recharging
1.Add refrigerant oil to compressor if necessary.
2.Renew the receiver/drier.
CAUTION: When a major repair has been
carried out, a leak test should be carried
out using inert gas.
3.Connect a Refrigerant Station to the high and
low pressure servicing connections.
CAUTION: Whenever the refrigerant
system is opened, the receiver/drier must
be renewed immediately before evacuating
and recharging the system.
4.Operate the refrigerant evacuation system
according to the manufactures instructions.
NOTE: If the vacuum reading is below
700mmHg after 15 minutes, suspect a leak
in the system. Partially recharge the
system and check for leaks using an electronic
leak tester. Check suction lines first, then run the
compressor for 5 minutes and then check the high
pressure lines.
CAUTION: The system must be Evacuated
immediately before recharging
commences. Delay between Evacuation
and Recharging is not permitted.

82AIR CONDITIONING
4
ADJUSTMENT 5.Operate the refrigerant recharging system
according to the manufactures instructions.
Refrigerant to charge system is 1.1 kg.
6.If the full charge has not been accepted by the
system, start the engine and run it at 1500
rev/min for a minimum of 2 minutes.
Switch on the air conditioning system, open the
vehicle windows, set the temperature control to
cold and switch the blower to maximum speed.
7.Consult Refrigerant Station Manual for correct
procedure to complete the charge.
8.Carry out the air conditioning system
performance test.LEAK TEST SYSTEM
The following instructions refer to an electronic type
Refrigerant Leak Detector for use with R134a, which
is the safest and most sensitive.
CAUTION: When a major repair has been
carried out, a leak test should be carried
out using an inert gas (see below).
1.Place the vehicle in a well ventilated area but
free from draughts, as leakage from the system
could be dissipated without detection.
2.Follow the instructions issued by the
manufacturer of the particular leak detector
being used.
3.Commence searching for leaks by passing the
detector probe around all joints and components,
refrigerant gas is heavier than air.
4.Insert the probe into an air outlet of the
evaporator or into the evaporator drain tube.
Switch the air conditioning blower on and off at
intervals of ten seconds. Any leaking refrigerant
will be gathered in by the blower and detected.
5.Insert the probe between the magnetic clutch
and compressor to check the shaft seal for
leaks.
6.Check all service valve connections, valve plate,
head and base plate joints and back seal plate.
7.Check the condenser for leaks at the pipe
unions.
8.If any leaks are found, the system must be
discharged before rectification.
9.Rectify any leaks and recheck for leaks during
evacuation prior to charging.
Leak test using inert gas
Use Nitrogen or Helium gas.
1.Connect gas line to recharging station.
2.Pressurise system to 3 bar.
3.Carry out leak test as above.

AIR CONDITIONING
5
ADJUSTMENT AIR CONDITIONING SYSTEM - PERFORMANCE
TEST
WARNING: R134a is hazardousSee
Repair, General Precautions
Carry out this test with bonnet and doors or windows
open, air conditioning switched on, temperature
control set to cold and blower at maximum speed. Set
the air supply control to supply fresh air.
1.Close low pressure valve on refrigerant station.
2.Close high pressure valve on refrigerant station.
3.Connect a Refrigerant Station to the high and
low pressure servicing connections.4.Insert dry bulb thermometer into cold air outlet
and position dry and wet bulb thermometer close
to outside air inlet.
Do not spill water from the wet thermometer
(psychrometer).
5.Start engine and run it at 1500 rev/min for 10
minutes with air conditioning switched on.
6.Read both pressure gauges and thermometers.
Check readings against table below with
humidity between 60% and 80%.
7.Switch off air conditioning, stop engine,
disconnect test equipment.
Performance range
Intake temperature Outlet temperature Low pressure High pressure
20 - 24°C4-10°C 18 - 28 lbf/in
2213 - 299 lbf/in2
1.2 - 1.9 bar 14.7 - 20.6 bar
25 - 29°C9-19°C 27 - 37 lbf/in2256 - 341 lbf/in2
1.9 - 2.6 bar 17.6 - 23.5 bar
30 - 35°C20-27°C 33 - 47 lbf/in2299 - 384 lbf/in2
2.3 - 3.2 bar 20.6 - 26.5 bar
Table 1
Ambient Compound Gauge High Pressure
Temperature Readings Gauge Readings
°C°F bar lbf/in
2bar lbf/in2
16 60 1,03-1,4 15-20 6,9-10,3 100-150
26,7 80 1,4-1,72 20-25 9,6-13,1 140-190
38 100 1,72-2,1 25-30 12,4-15,5 180-225
43,5 110 2,1-2,4 30-35 14,8-17,2 215-250