air condition LAND ROVER DEFENDER 1996 Repair Manual

74WHEELS AND TYRES
2
FAULT DIAGNOSIS FAULT - SYMPTOMS
Vibration through steering wheel
1.Check tyre pressures
See Repair, Tyre
Pressures
.
2.Check condition of tyres
See Tyre Wear Chart.
3.Check front wheel alignment
See STEERING,
Adjustment, Front Wheel Alignment
.
4.Check wheel balance
See Repair, Wheel
Balancing
.
NOTE: In the event that any apparent
vibration is not eliminated at this stage
See PROPELLER SHAFTS, Fault
diagnosis, Vibration Harshness
.
NOTE: In the event that any apparent
vibration is not eliminated at this stage, go
to steering Fault Diagnosis, Fault -
Symptom (Steering vibration, road wheel
shimmy/wobble)
See STEERING, Fault diagnosis,
Steering Faults
.
NOTE: Radial ply tyres have a flexible
sidewall, which produces a sidewall bulge
making the tyre appear under-inflated.
This is a normal condition for radial ply tyres. Do
not attempt to reduce this bulge by over-inflating
the tyre.
Key to illustration
1.Correct inflation.
2.Under-inflation.
3.Over-inflation.
4.Tread contact with road.

WHEELS AND TYRES
1
REPAIR REV: 05/99 GENERAL INFORMATION
WARNING: This is a multi-purpose vehicle
with wheels and tyres designed for both
on and off road usage. Only use wheels
and tyres specified for use on the vehicle.
The vehicle is equipped with tubeless 'S','T' or 'H'
rated radial ply tyres as standard equipment. The
tyres are of European metric size and must not be
confused with the "P" size metric tyres available in
North America.
Vehicle wheel sets, including spare wheel, must be
fitted with the same make and type of tyre to the
correct specification and tread pattern. Under no
circumstances must cross-ply or bias-belted tyres be
used.
For tyre specification and pressures
See GENERAL
SPECIFICATION DATA, Information, Wheels and
Tyres
.
Steel wheels
Tubeless tyres are mounted on 7.0 inch wide by 16
inch diameter steel wheels.
Alloy Wheels
Tubeless tyres are mounted on 7.0 inch wide by 16
inch diameter cast aluminium alloy wheels. The
surface has a paint finish covered with a clear
polyurethane lacquer. Care must be taken when
handling the wheel to avoid scratching or chipping the
finish.
The alloy wheel rim is of the asymmetric hump
type incorporating a safety hump to improve
location of the tyre bead in its seat. If difficulty is
experienced in fitting tyres to this type of rim
See
Tyre Fitting
.
WARNING: DO NOT fit an inner tube to an
alloy wheel.TYRE INSPECTION
Inspect tyres at weekly intervals to obtain maximum
tyre life and performance and to ensure compliance
with legal requirements. Check for signs of incorrect
inflation and uneven wear, which may indicate a need
for balancing or front wheel alignment,
See Fault
diagnosis, Tyre Wear Chart
, if the tyres have
abnormal or uneven wear patterns.
Check tyres at least weekly for cuts, abrasions, bulges
and for objects embedded in the tread. More frequent
inspections are recommended when the vehicle is
regularly used in off road conditions.
To assist tyre inspection, tread wear indicators are
moulded into the bottom of the tread grooves, as
shown in the illustration above.
When the tread has worn to a depth of 1.6 mm the
indicators appear at the surface as bars which
connect the tread pattern across the width of the tread
as shown in the illustration above.

74WHEELS AND TYRES
2
REPAIRREV: 05/99 When the indicators appear in two or more adjacent
grooves, at three locations around the tyre, a new tyre
must be fitted.
NOTE: DO NOT attempt to interchange
tyres, e.g. from front to rear, as tyre wear
produces characteristic patterns
depending on their position. If tyre position is
changed after wear has occured, the performance
of the tyre will be adversely affected.
NOTE: Territorial vehicle regulations
governing tyre wear MUST be adhered to.
WHEELS INSPECTION
Regularly check the condition of the wheels. Replace
any wheel that is bent, cracked, dented or has
excessive runout.
VALVES INSPECTION
Check condition of inflation valve. Replace any valve
that is worn, cracked, loose, or leaking air.TYRE PRESSURES
Maximum tyre life and performance will be
obtained only if tyres are maintained at the correct
pressures.
Tyre pressures must be checked at least once a week
and preferably daily, if the vehicle is used off road.
The tyre inflation pressure is calculated to give the
vehicle satisfactory ride and steering characteristics
without compromising tyre tread life. For
recommended tyre pressures in all conditions
See
GENERAL SPECIFICATION DATA, Information,
Wheels and Tyres
.
Always check tyre inflation pressures using an
accurate gauge and inflate tyres to the
recommended pressures only.
Check and adjust tyre pressuresONLYwhen the
tyres are cold, vehicle parked for three hours or more,
or driven for less than 3.2 km (2 miles) at speeds
below 64 km/h (40 mph). Do not reduce inflation
pressures if the tyres are hot or the vehicle has been
driven for more than 3.2 km (2 miles) at speeds over
64 km/h (40 mph), as pressures can increase by 0.41
bars (6 lb/in
2) over cold inflation pressures.
CheckALLtyre pressures including the spare. Refit
the valve caps as they form a positive seal and keep
dust out of the valve.

74WHEELS AND TYRES
4
REPAIR Static balance
Wheel tramp
A- Heavy spot.
B- Add balance weights here.
C- Centre line of spindle.
Static balance is the equal distribution of weight
around the wheel. A statically unbalanced wheel will
cause a bouncing action called wheel tramp. This
condition will eventually cause uneven tyre wear.Dynamic balance
Wheel shimmyA- Heavy spot.
B- Add balance weights here.
C- Centre line of spindle.
Dynamic balance is the equal distribution of weight on
each side of the centre line so that when the wheel
spins there is no tendency for side to side movement.
A dynamically unbalanced wheel will cause wheel
shimmy.

HEATING AND VENTILATION
1
DESCRIPTION AND OPERATION HEATING AND VENTILATION SYSTEM
Description
The heating and ventilation system is standard on all
models. Air conditioning is an optional system which
provides fully integrated climate control for the vehicle
interior.The heater assembly, comprising a matrix housed in a
distribution unit and a variable speed blower motor, is
located on one side of the engine compartment and
attached directly to the fascia bulkhead.
The heating controls are positioned on the outside of
the instrument binnacle and cable linked to
mechanical flaps in the distribution unit.
Heater assembly
1.Heater distribution unit
2.Fixings, heater to fascia bulkhead
3.Heater matrix
4.Blower motor housing
5.Circlip, impeller to blower motor
6.Impeller
7.Resistor unit and harness connector8.Fixings, blower motor mounting plate
9.Mounting plate, blower motor
10.Blower motor
11.Fixings, blower motor to mounting bracket
12.Temperature flap, air flow to heater matrix
13.Air flap, air supply to plenum chamber (heater
duct)

80HEATING AND VENTILATION
6
REPAIR HEATER CONTROL CABLE - AIR DISTRIBUTION
Service repair no - 80.10.12
Remove
1.Disconnect battery.
2.Remove steering wheel
See STEERING,
Repair, Steering wheel.
3.Remove steering column nacelleSee
STEERING, Repair, Steering column nacelle.
4.Remove instrument panelSee INSTRUMENTS,
Repair, Instrument panel.
5.Remove retaining screws and pull off air
distribution and temperature control lever knobs.
6.Remove 3 screws and detach side cover,
complete with control lever assembly.
7.Remove 2 screws securing control lever
assembly to side cover and remove cover. Note
plastic screw spacers fitted between cover and
control lever assembly and retain.
8.Remove small bolt and release outer cable
retaining clip.
9.Slacken grub screw and release inner cable from
clevis.
10.Remove lower fascia panel assembly
See
CHASSIS AND BODY, Repair, Lower fascia
panel (heater duct) assembly.
11.Remove 19 screws and lift off heater duct cover.
12.Slacken vent flap trunnion fixing, release air
distribution control cable and remove from
heater duct.
13.Check condition of foam sealant on heater duct
cover and renew if necessary.

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.