ECU LAND ROVER DISCOVERY 1995 Workshop Manual

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.

AIR CONDITIONING
1
FAULT DIAGNOSIS AIR CONDITIONING FAULTS
FAULT CAUSE REMEDY
1. Incorrect voltage. 1. Check voltage.
A.2. Open or defective fuse or relay. 2. Check and replace as necessary.
BLOWER3. Loose wire connection including 3. Check system wires; tighten
MOTORground. all connections.
INOPERATIVE4. Switch open or defective. 4. Replace switch.
OR SLOW5. Tight, worn, or burnt motor 5. Replace motor.
RUNNINGbearings.
6. Open rotor windings. 6. Replace motor.
7. Worn motor brushes. 7. Replace motor.
8. Shaft binding-blade misaligned. 8. Check alignment. Repair or replace
as necessary.
9. Defective resistors 9. Rectify or replace.
1. Incorrect voltage. 1. Check voltage.
2. Open or defective fuse or relay. 2. Check and replace as necessary.
B.3. Defective thermostat control or 3. Replace thermostat or
COMPRESSORpressure switch. pressure switch.
CLUTCH4. Shorted or open field coil. 4. Replace coil.
INOPERATIVE5. Bearing seized (clutch will not 5. Replace clutch pulley assembly.
disengage).
6. Refrigeration circuit problem causing
heavy load and excessive drive
torque.6. Check and rectify.
1. Incorrect alignment. 1. Check alignment; repair as
necessary.
2. Loose belt. 2. Adjust to proper tension.
C.3. Compressor not mounted securely. 3. Repair as necessary.
COMPRESSOR4. Bearing in clutch-pulley 4. Remove clutch and replace
CLUTCHassembly not pressed in. clutch pulley assembly.
NOISY5. Low voltage to clutch. 5. Check connections and voltage.
6. Clutch will not spin freely. 6. Refer to B5 above.
7. Oil on clutch face. 7. Check compressor seals for leaks.
8. Slipping clutch. 8. Refer to C5 above. Then check air
gap.
9. Overloaded or locked compressor. 9. Repair or replace compressor.
10. Icing. 10. Check for suction line frosting.
Replace expansion valve if
necessary.
Replace receiver/drier if necessary.
D.1. Motor and/or blades improperly 1. Check mountings, adjust as
CONDENSERmounted. necessary.
VIBRATION2. Foreign matter build-up on 2. Clean blades with a suitable
blades. non-inflammable cleaner.
3. Excessive wear of motor bearings. 3. Replace motor.

AIR CONDITIONING
3
FAULT DIAGNOSIS FAULT CAUSE REMEDY
1. Overcharge of refrigerant. 1. Discharge, evacuate and charge
system.
A.
HIGH HEAD2. Air in system. 2. Discharge system, fit new drier,
PRESSUREevacuate and charge system.
3. Condenser air passage clogged 3. Clean condenser of debris.
with dirt or other foreign matter.
4. Condenser fan motor defective. 4. Replace motor.
5. Incorrect voltage to fan motor. 5. Check voltage.
1. Undercharge of refrigerant; 1. Evacuate and charge system.
B.evident by bubbles in sight Check for leakage.
LOW HEADglass while system is operating
PRESSURE2. Split compressor gasket or 2. Replace gasket and/or reed
leaking valves. valve. Fit new drier, evacuate and
charge system.
3. Defective compressor. 3. Repair or replace compressor.
1. Loose drive belt 1. Check belt tension.
2. Refrigerant flooding through
evaporator into suction line; evident
by ice on suction line and suction
service valve.2. Check thermobulb. Bulb should be
securely clamped to clean horizontal
section of copper suction pipe.
C.3. Expansion valve stuck open. 3. Replace expansion valve.
HIGH4. Leaking compressor valves, 4. Replace valves and/or
SUCTIONvalve gaskets and/or service gaskets. Fit new drier
PRESSUREvalves. evacuate and charge system.
5. Receiver/drier blocked; evident 5. Fit new drier, evacuate
by temperature difference and charge system.
between input and output lines.
1. Expansion valve thermobulb not 1. Warm thermobulb with hand.
operating. Suction should rise rapidly to 1.4 bar
20 lb/in
2or more. If not replace
expansion valve.
2. Expansion valve sticking closed. 2. Check inlet side screen.
D.Clean if clogged. Refer
LOWto C-2 and C-3.
SUCTION3. Moisture freezing in expansion valve
orifice. Valve outlet tube will frost
while inlet hose tube will have little or
no frost. System operates
periodically.3. Fit new drier, evacuate and charge
system.
4. Dust, paper scraps, or other debris
restricting evaporator blower grille4. Clean grilles as required.
5. Defective evaporator blower motor,
wiring, or blower switch.5. Refer to Fault Diagnosis Chart for
blower motor.

82AIR CONDITIONING
4
FAULT DIAGNOSISFAULT CAUSE REMEDY
E.
NOISY
EXPANSION
VALVE
(steady hissing)1. Low refrigerant charge; evident by
bubbles in sight glass.1. Leak test. Repair or replace
components as required.
F.1. Expansion valve not operating 1. Refer to C-2, C-3, D-1
INSUFFICIENTproperly. and E.
COOLING2. Low refrigerant charge-evident 2. Refer to B-1 and E.
by bubbles in sight glass.
3. Compressor not pumping. 3. Refer to B-2 and B-3
G.1. Belt tension. 1. Adjust belt tension.
COMPRESSOR2. Excessive head pressure. 2. Refer to A-1 through
BELTA-4 and C-6.
SLIPPING3. Incorrect alignment of pulleys 3. Repair as needed.
or worn belt not riding properly.
4. Nicked or broken pulley. 4. Replace as needed.
5. Seized compressor. 5. Replace compressor.
1. Loose or missing mounting bolts. 1. Repair as necessary.
2. Broken mounting bracket. 2. Replace bracket.
3. Loose flywheel or clutch 3. Repair as necessary.
retaining bolt.
H.4. Rough idler pulley bearing. 4. Replace bearing.
ENGINE5. Bent, loose, or improperly 5. Repair as necessary.
NOISEmounted engine drive pulley.
AND/OR6. Defective compressor bearing. 6. Replace bearing.
VIBRATION7. Insecure mountings of 7. Repair as necessary.
accessories; generator, power
steering, air filter, etc.
8. Excessive head pressure. 8. Refer to A-1, A-2, A-3
A-4 and C-6.
9. Incorrect compressor oil level. 9. Refer to compressor Oil
Level Check.
HEATER AND AIR CONDITIONING - CIRCUIT
DIAGRAMS
1.For details of heating and air conditioning
electrics
See Electrical Trouble Shooting
Manual.

82AIR CONDITIONING
2
REPAIR PERIODIC MAINTENANCE
Routine servicing, apart from visual checks, is not
necessary. The visual inspections are as follows:
Condenser
With a water hose or air line, clean the fins of the
condenser to remove flies, leaves, etc. Check the pipe
connections for signs of oil leakage.
Compressor
Check pipe connections for signs of oil leakage.
Check flexible hoses for swelling. Examine the
compressor belt for tightness and condition.
Sight glass and Receiver/Drier
Examine the sight glass for bubbles with the system
operating. Check connections for leakage.
Evaporator
Examine the refrigeration connections at the unit. If
the system should develop a fault, or if erratic
operation is noticed,
See Fault diagnosis,
Refrigeration System Faults
RECEIVER DRIER
Service repair no - 82.17.01
Remove
CAUTION: If receiver/drier is to be refitted,
the ports must be blanked off immediately
on disconnection. Exposed life of unit is
only 15 minutes.
1.Disconnect battery negative lead.
2.Recover refrigerant from system.
See
Adjustment, Refrigerant Recovery Recycling
Recharging
WARNING: Wear eye and hand protection
when disconnecting components
containing refrigerant. Plug all exposed
connections immediately.
3.Remove 3 screws from bonnet locking platform
and remove radiator grille.
Automatic gearbox
4.Remove 4 bolts securing transmission oil cooler
to body.

AIR CONDITIONING
3
REPAIR 5.Disconnect 2 pipe unions from oil cooler. Use a
second wrench to support hose adapter.
6.Remove transmission oil cooler. Seal
connections.
All models
7.Remove bolt securing receiver/drier clamp.
WARNING: Wear eye and hand protection
when disconnecting components
containing refrigerant. Plug all exposed
connections immediately.
8.Move receiver/drier just sufficiently to gain
access to pipe flange bolts without distorting the
pipes.
9.Remove bolt securing each pipe flange to
receiver/drier.
10.Disengage pipe flanges and withdraw
receiver/drier from mounting bracket.
11.Remove 'O' ring from each pipe flange.Refit
12.Fit new 'O' ring to each pipe flange, lubricate
with refrigerant oil.
13.Position receiver/drier in mounting bracket with
inlet and outlet connections correctly aligned.
14.Engage pipe flanges, fit bolts in turn and tighten.
15.Fit clamp bolt.
Automatic gearbox
16.Refit transmission oil cooler. Use a second
wrench to support pipe unions.
17.Check gearbox fluid level, top-up if necessary.
All models
18.Evacuate and recharge air conditioning system.
See Adjustment, Refrigerant Recovery
Recycling Recharging
19.Perform a leak test on disturbed joints.
20.Carry out a functional check.

AIR CONDITIONING
5
REPAIR COMPRESSOR
Service repair no - 82.10.20
Remove
1.Disconnect battery negative lead.
2.Recover refrigerant from air conditioning system.
See Adjustment, Refrigerant Recovery
Recycling Recharging
3.Remove screws retaining centre panel to fan
cowl
4.Remove centre panel.
V8i engine illustrated
5.Remove 2 bolts securing hose flanges to
compressor.
WARNING: Wear eye and hand protection
when disconnecting components
containing refrigerant. Plug all exposed
connections immediately.6.Disconnect high pressure hose from
compressor.
7.Disconnect low pressure hose from compressor.
8.Remove 'O' ring from each flange.
9.Disconnect electrical lead from compressor
clutch.
10.Release drive belt from compressor pulley.
See
ENGINE, Repair, Drive Belt
11.Remove 4 bolts securing compressor to
mounting bracket.
12.Remove compressor from mounting bracket.
Refit
13.New compressor to be fitted: Drain oil from new
compressor outlet port. Drain and measure oil
from old compressor. Measure new oil equal to
amount drained from old compressor, add 30 ml
extra to this amount and refill new compressor
through outlet port.
14.Locate compressor in mounting bracket, fit bolts.
Tighten to
25 Nm.
15.Connect electrical lead to compressor clutch.
16.Fit new 'O' rings to high and low pressure hose
flanges, lubricate with refrigerant oil.
17.Engage hose flanges, fit bolts. Tighten to
10
Nm.
18.Fit compressor drive belt.See ENGINE, Repair,
Drive Belt
19.Fit centre panel to fan cowl.
20.Evacuate and recharge air conditioning system.
See Adjustment, Refrigerant Recovery
Recycling Recharging
21.Perform a leak test on disturbed joints.
22.Carry out a functional check.