LAND ROVER DISCOVERY 1995 Workshop Manual

80HEATING AND VENTILATION
4
DESCRIPTION AND OPERATION Air direction flap
Flap moves across mixing chamber to direct the air
flow away from the heater matrix.
Air temperature flap
Control at HOT, flaps fully closed. All air flow passes
through heater matrix. As control is moved towards
COLD the flaps progressively open directing air flow
away from the heater matrix.
Control at COLD, flaps fully open.
V8 Engine:When both controls are at COLD, 2
micro-switches are closed and operate a vacuum
valve which closes the coolant valve.Air conditioning
When an air conditioning unit is fitted, the mechanical
operation of the heater controls remains unaltered.
However the air conditioning evaporator is positioned
in front of the mixing chamber through which all air
flow passes.

HEATING AND VENTILATION
1
FAULT DIAGNOSIS HEATER OUTPUT
Symptom:-
Heater emits cold air.
1.Engine running: Check coolant valve opens as a
temperature control is moved from COLD.
2.Check for engine running cold.
See COOLING
SYSTEM, Fault diagnosis, Engine Runs Cold
3.Check heater pipes and hoses for blockage or
restriction.
4.Check heater matrix for blockage or restriction,
flush system.
Heater emits warm air.
5. Engine running:Check coolant valve closes
when both temperature controls are moved to
COLD.

HEATING AND VENTILATION
1
REPAIR HEATER BLOWER SWITCH AND ILLUMINATION
BULB
Service repair no - 80.10.22 - Switch
Service repair no - 86.48.73 - Bulb
Remove
1.Pull 3 knobs from rotary controls.
2.Pull knob from blower switch.
3.Remove 2 screws retaining graphics panel.
4.Remove graphics plate.
5.Remove capless bulb.
6.Remove 4 screws retaining switch.
7.Remove switch panel. Use plastic tube to assist
removal.
Blower switch
8.Pull blower switch from rear of panel.
9.Disconnect multiplug and remove blower switch.
Refit
10.Reverse removal procedure.HEATER CONTROL UNIT
Service repair no - 80.10.42.
Remove
1.Disconnect battery negative lead.
2.Pull 3 knobs from rotary controls.
3.Pull knob from blower switch.
4.Remove 2 retaining screws and remove
graphics panel.
5.Remove 4 screws retaining switch.
6.Remove switch panel.
7.Release fascia centre louvre vent panel from its
fitted position to gain access to rear of panel.
See CHASSIS AND BODY, Repair, Dash
Panel Central Louvre Panel

80HEATING AND VENTILATION
2
REPAIR 8.Disconnect 4 multiplugs and position harness
aside.
NOTE:Do not carry out further
dismantling if component is removed for
access only.
9. Fan speed switch:remove fan speed switch
slide and push out fan speed switch.
10.Pull out light bulb disconnect terminals and
remove fan speed light strip.
11.Unclip 3 heater control cables from control unit.
12. Microswitch:Unclip 3 micro switches.
13.Cut cable tie and release wiring harness from
control unit.
14.Remove heater control unit.
Refit
15.Reverse removal procedure. Check the
satisfactory function of the controls before fitting
louvre vent panel.CONTROL CABLES
Service repair no - 80.10.06 - Air flow
Service repair no - 80.10.25 - Temperature control
RH
Service repair no - 80.10.26 - Temperature control
LH
Remove
1.Release fascia centre louvre vent panel from its
fitted position to gain access to rear of panel.
See CHASSIS AND BODY, Repair, Dash
Panel Central Louvre Panel
2.Open glove box, manoeuvre side springs
through cut-outs and lower lid.

HEATING AND VENTILATION
3
REPAIR Air direction
3.Set control fully clockwise
4.Release outer cable from 2 clips on unit.
5.Release cable from stud on flap lever.
6.Remove control cable from control lever.
Temperature
7.Set RH control fully clockwise, LH control fully
anti-clockwise
8.Release outer cable from 2 clips on unit.
9.Release cable from stud on flap lever.
10.Remove control cable from control lever.
Refit
11.Reverse removal procedure. Check the
satisfactory function of the controls before fitting
louvre vent panel.RESISTOR UNIT
Service repair no - 80.20.17
Remove
1.Open glove box, manoeuvre side springs
through cut-outs and lower lid.
2.Remove 2 screws securing resistor unit to
trunking.
3.Disconnect multiplug and remove resistor unit.
Refit
4.Reverse removal procedure.

80HEATING AND VENTILATION
4
REPAIR WATER VALVE
Service repair no - 80.10.16
Remove
1.Disconnect vacuum pipe from water valve.
2.Slacken 4 clips securing hoses to water valve.
3.Use a thin blade to break seal between hoses
and nozzles
4.Disconnect heater inlet hose from valve.
NOTE: A quantity of coolant will be
released.
5.Disconnect heater outlet hose from valve.
6.Lever valve from coolant pipe hoses.
Refit
7.Reverse removal procedure. Lightly lubricate
water valve nozzles with petroleum jelly.
8.Reverse removal procedure. Top-up engine
coolantVACUUM SWITCH - WATER VALVE
Service repair no - 80.10.36
Remove
1.Release emission pipe from retaining clip.
2.Remove bolt securing switch to bulkhead.
3.Disconnect multiplug from switch.
4.Disconnect 2 vacuum pipes and remove vacuum
switch.
Refit
5.Reverse removal procedure.

HEATING AND VENTILATION
5
REPAIR RECIRCULATION SWITCH
Service repair no - 80.10.27
Remove
1.Release fascia centre louvre vent panel from its
fitted position to gain access to rear of panel.
See CHASSIS AND BODY, Repair, Dash
Panel Central Louvre Panel
2.Disconnect multiplug from switch
3.From the rear, push switch out of panel.
Refit
4.Reverse removal procedure.RECIRCULATION FLAP SOLENOID
Service repair no - 80.10.43
Remove
1.Open glove box, manoeuvre side springs
through cut-outs and lower lid.
2.Remove 2 locknuts securing cruise control ECU
to bracket.
3.Position cruise control ECU aside.
4.Remove 2 screws securing recirculation
solenoid to casing.
5.Release solenoid from lever.
6.Disconnect multiplug and remove solenoid.
Refit
7.Reverse removal procedure.

80HEATING AND VENTILATION
6
REPAIR BLOWER MOTOR UNIT - HEATER AND AIR
CONDITIONING
Service repair no - 80.20.17
Service repair no - 82.25.54.
Remove
1.Move seats to rear most position.
2.Disconnect battery negative lead.
3.Remove fascia panel assembly.
See CHASSIS
AND BODY, Repair, Dash Panel Assembly
4.Remove 2 nuts securing lower brackets to
toeboard.
5.Manoeuvre blower unit from heater unit and
remove.
Refit
6.Reverse removal procedure. Ensure seal
between blower and heater unit is tight.BLOWER MOTOR
Service repair no - 80.20.17
Service repair no - 82.25.33.
Remove
1.Remove blower motor unit.
See Blower Motor
Unit - Heater and Air Conditioning
2.Release wiring harness retaining clip.
3.Remove 3 screws securing casing.
4.Remove blower motor assembly.

HEATING AND VENTILATION
7
REPAIR
5.Remove fan retaining clip.
6.Remove fan.
7.Remove 2 screws securing motor to casing.
8.Remove blower motor.
Refit
9.Reverse removal procedure.HEATER MATRIX
Service repair no - 80.20.29
Remove
1.Remove heater unit.
See AIR CONDITIONING,
Repair, Heater and Cooler Unit
2.Remove evaporator.See AIR CONDITIONING,
Repair, Evaporator and Expansion Valve
3.Remove 2 screws and remove RH side footwell
outlet.
4.Remove heater pipe clips.
5.Slide heater matrix from casing.
6.Release 2 clips and remove 2 heater pipes from
matrix.
Refit
7.Reverse removal procedure.

HEATING AND VENTILATION
1
SPECIFICATIONS, TORQUE TORQUE VALUES
NOTE: Torque wrenches should be regularly checked for accuracy to ensure that all fixings are
tightened to the correct torque.
Nm
METRIC
M5 6......................................................................................................
M6 9......................................................................................................
M8 25.....................................................................................................
M10 45...................................................................................................
M12 90...................................................................................................
M14 105..................................................................................................
M16 180..................................................................................................
UNC / UNF
1/4 9......................................................................................................
5/16 24...................................................................................................
3/8 39.....................................................................................................
7/16 78...................................................................................................
1/2 90.....................................................................................................
5/8 136....................................................................................................
Torque values above apply to all screws and bolts used unless otherwise specified.