electrical LAND ROVER DISCOVERY 1995 Workshop Manual

86ELECTRICAL
10
DESCRIPTION AND OPERATION Radio frequency system
The RF system uses frequencies according to market
and both ECU and handset are colour coded:
Territory ECU/Handset............................... Frequency..................
Europe Blue/Blue.................................. 433.92 MHz.........................
NAS Green/Green....................................... 315.00 MHz....................
Japan Green/Green.................................... 315.00 MHz....................
Gulf Green/Green....................................... 315.00 MHz....................
Rest of World Green/Brown........................ 315.00 MHz...................
NOTE: In service NAS, Japan and Gulf will
have the handset changed to brown.
Passive coil
The passive coil excites a receiving coil in the handset
causing it to automatically transmit a remobilisation
signal to the ECU.
Inertia switch and central door locking
Actuation of the inertia switch will cause the doors to
be unlocked. A time-out period (programmable
between 0-5 minutes) will ensue, during which all CDL
and alarm activity is disabled.
NOTE: This feature only applies when the
starter switch is in the on position.
Handset
Under normal circumstances pressing the respective
buttons on the handset once, will unlock or lock the
vehicle. If operating the handset does not achieve the
desired effect
See Repair, Handset.
Functional detail
For full functional details and circuit diagrams
See
Electrical Trouble Shooting Manual..
Vehicle traceability
All Land Rover vehicles are fitted with a multitude of
discreet security features to prevent theft or assist
recovery in the event of a vehicle being stolen. All
vehicles are traceable, since it is impossible to
remove all security identification.

ELECTRICAL
11
DESCRIPTION AND OPERATION ANTI-THEFT ALARM BUILT-IN TEST (96 MODELS)
NOTE: The handset should be detached
from the key to allow perimetric testing of
the alarm system. The system will
automatically switch to volumetric testing if the
handset is in close proximity to the starter switch.
The built-in test procedure can be accessed providing
the following conditions exist:
Alarm disarmed.
Ignition off.
Doors unlocked.
Bonnet[hood] closed.
The test mode can be entered by completing the
following instructions within 5 seconds:
1.Open bonnet.
2.Turn starter switch on.
3.Open driver's door (far enough to activate
switch).
4.Turn starter switch off.
5.Turn starter switch on.
If the test mode has been correctly accessed, the
sounder/horn will operate briefly and the anti-theft
alarm indicator and hazard warning lights will flash.
Perimetric tests
The anti-theft alarm indicator light and the hazard
warning lights will flash when:
1.Door switches are activated;
2.The bonnet is opened;
3.Sill switches are activated;
4.Key switches are activated.
NOTE: Operation of key switches can be
verified by turning the key in the relevent
direction so as not to simultaneously
activate the sill switch. If the key switch changes
state, the change should be detected but the sill
switch will not be activated.
Volumetric tests
Press the unlock button or move the handset close to
the starter switch to disable perimetric testing and
enable volumetric testing. If movement is detected
within the vehicle by the ultrasonic sensor it will be
indicated by flashing the anti-theft alarm indicator and
hazard warning lights.
NOTE: Exit anti-theft alarm built-in test by
turning starter switch to the off position.

ELECTRICAL
1
FAULT DIAGNOSIS GENERAL INFORMATION
The electrical fault diagnostic tool on Discovery
vehicles is Testbook. Detailed information of electrical
systems, component locations and circuit diagrams
are covered in the Discovery Electrical
Troubleshooting Manual.
See INTRODUCTION,
Information, Fault Diagnostic Equipment
This section covers checks of the charging and
ignition system.
GENERATOR TESTING
Service repair no - 86.10.01
Charging system check
1.Check battery is in good condition, with an open
circuit voltage of at least 12.6 V. Recharge or
substitute battery to carry out test.
2.Check drive belt condition.
See SECTION 10,
Maintenance, Under Bonnet [Hood]
Maintenance
3.Check battery connections are clean and tight.
4.Check generator connections are clean and
tight.
5.Ensure there is no drain on battery from, for
example, interior, under bonnet [hood] or door
edge lamps.
Generator test
Following instructions refer to use of suitable test
equipment using a carbon pile rheostat.
6.Connect test equipment referring to
manufacturer's instructions.
7.Start engine and run at 3000 rev/min without
accessory load.
8.Rotate carbon pile load control to achieve
greatest output (amps) without allowing voltage
to fall below 12.0 V. A reading in amps, of
generator output, minus 10% to allow for EFI
and Ignition loss, should be obtained.
9.Run engine at 3000 rev/min, switch selector to
regulator test, read voltmeter. A reading of 13.6
to 14.4 V should be obtained.
10.Switch selector to diode/stator test, switch on
headlamps to load generator. Raise engine
speed to 3000 rev/min, read voltmeter, needle
must be within 'OK' range.TESTING IN POSITION
Charging circuit resistance test.
1.Connect a low range voltmeter between
generator terminal marked B+ and positive
terminal of battery.2.Switch on headlamps, start engine. Run engine
at approximately 3000 rev/min. Note voltmeter
reading.
3.Transfer voltmeter connections to frame of
generator and negative terminal of battery, and
again note voltmeter reading.
4.If reading exceeds 0.5 volt on positive side or
0.25 volt on negative side, there is a high
resistance in charging circuit which must be
traced and remedied.

86ELECTRICAL
2
FAULT DIAGNOSIS LUCAS CONSTANT ENERGY IGNITION SYSTEM -
V8i
Preliminary checks
Inspect battery cables and connections to ensure they
are clean and tight. Check electrical condition of
battery.
Inspect all L.T. connections, ensure they are clean
and tight. Check H.T. leads are correctly positioned
and not shorting to ground against any engine
components. Wiring harness and individual cables
should be firmly fastened to prevent chaffing.
Pick-up air gap
Check air gap between pick-up limb and reluctor teeth
is 0.20 - 0.35 mm, using a non-ferrous gauge.
NOTE: Air gap is set initially at factory and
will only require adjusting if tampered with
or when pick-up module is replaced.
TEST 1:
H.T. Sparking
Remove coil/distributor H.T. lead from distributor
cover and hold approximately 6mm from engine block,
using suitable insulated pliers. Switch ignition 'On' and
operate starter.
Regular sparking indicates fault in H.T. distribution,
plugs, timing or fuelling, proceed to Test 6. If no spark
or weak spark occurs proceed to Test 2.TEST 2:
L.T. Voltage
Switch ignition 'On' - engine stationary.
(a) Connect voltmeter to points in circuit indicated
by V1 to V4 and make a note of voltage
readings.
(b) Compare voltages obtained with specified
values listed below:
Expected readings
V1 More than 12 volts.
V2 1 volt maximum below volts at V1.
V3 1 volt maximum below volts at V1.
V4 0 volt - 0.1 volt.
(c) If all readings are correct proceed to Test 3.
(d) Check incorrect reading(s) with chart to identify
area of possible faults, i.e. faults listed under
heading SUSPECT and rectify.
(e) If coil and amplifier is suspected, disconnect L.T.
lead at coil, repeat V3. If voltage is still incorrect,
fit new coil. If voltage is now correct, check L.T.
lead, if satisfactory fit new amplifier.
(f) If engine will not start proceed to Test 3.

ELECTRICAL
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FAULT DIAGNOSIS 1 2 3 4 SUSPECT
L * * * DISCHARGED BATTERY
* L L * IGN. SWITCH AND/OR
WIRING
* * L * COIL OR AMPLIFIER
* * * H AMPLIFIER GROUND
Key
*Expected Voltage
HVoltage higher than expected
LVoltage lower than expectedTEST 3:
Amplifier Switching
Connect voltmeter between battery positive (+ve)
terminal and H.T. coil negative (-ve) terminal.
Voltmeter should register 0 volts.
Switch ignition 'On', voltmeter should still register 0
volts.
Crank engine, voltmeter reading should increase
when cranking, in which case proceed to Test 5.
If no increase in voltage during cranking proceed to
Test 4.

86ELECTRICAL
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FAULT DIAGNOSIS TEST 4:
Pick-up Coil Resistance
Remove amplifier.
Connect ohmmeter leads to two pick-up terminals in
body of distributor.
The ohmmeter should register between 2k and 5k
ohm if pick-up is satisfactory. If ohmmeter reading is
correct, check all connections between pick-up and
amplifier, if satisfactory, fit new amplifier. If engine still
does not start carry out Test 5.
Change pick-up if ohmmeter reading is incorrect. If
engine still does not start proceed to Test 5.TEST 5:
Coil H.T. Sparking
Remove existing coil/distributor H.T. lead and fit test
H.T. lead to coil tower. Using suitable insulated pliers,
hold free end about 6mm from engine block and crank
engine. There should be good H.T. sparking.
If weak or no sparking, fit new coil, repeat test.
H.T. sparking good, repeat test with original H.T. lead.
If sparking is good carry out Test 6.
If weak or no sparking, fit new H.T. lead, if engine will
not start carry out Test 6.

ELECTRICAL
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FAULT DIAGNOSIS TEST 6:
Rotor Arm
Remove distributor cover. Disconnect coil H.T. lead
from cover, using insulated pliers hold about 3mm
above rotor arm electrode and crank the engine.
There should be no H.T. sparking between rotor and
H.T. lead. If satisfactory carry out Test 7.
If H.T. sparking occurs, an earth fault on rotor arm is
indicated. Fit new rotor arm. If engine will not start
carry out Test 7.
TEST 7:
Visual and H.T. Cable Checks
Examine: Should be:
1. Distributor Cover Clean, dry, no tracking marks.....................................................
2. Coil Top Clean, dry, no tracking marks....................................................................
3. H.T. Cable Insulation Must not be cracked, chafed or perished...............................................
4. H.T. Cable Continuity Must not be open circuit..............................................
5. Sparking Plugs Clean, dry, and set to correct gap........................................................
NOTE:
1. Reluctor Must not foul pick-up or leads...................................................................
2. Rotor and Insulation Cover Must not be cracked or show signs of tracking marks.....................................

ELECTRICAL
1
ADJUSTMENT IGNITION TIMING
Service repair no - 86.35.15
Adjust
1.It is essential that following procedures are
adhered to. Inaccurate timing can lead to serious
engine damage and additionally create failure to
comply with emission regulations. If timing is
being checked in vehicle, air conditioning
compressor must be disengaged.
2.On initial engine build, or if distributor has been
disturbed for any reason, ignition timing must be
set statically to 6°B.T.D.C.
NOTE: This approximate setting is made
only to ensure that engine may be started.
CAUTION: On no account must engine be
started before this operation is carried out.Equipment required :-
Calibrated Tachometer
Stroboscopic lamp
3.Couple stroboscopic timing lamp and tachometer
to engine following manufacturer's instructions.
4.Disconnect vacuum hose from distributor.
5.Start engine. With no load, and without
exceeding 3,000 rev/min run engine until normal
operating temperature is reached. (Thermostat
open). Check that engine idles within tolerance
specified in data section.
6.Idle speed for timing purposes must not exceed
800 rev/min.
7.Run engine at idle speed and check timing using
stroboscope light on timing marker and pointer.
WARNING: Keep hands and equipment
away from belt.
8.If timing is not as specified, switch off engine.
Loosen distributor clamp bolt and turn distributor
to advance or retard ignition as necessary.
Tighten clamp bolt, start engine and recheck
timing.
WARNING: Personal injury may result if an
attempt is made to adjust distributor whilst
engine is running.
9.Upon completion, switch off engine and retighten
distributor clamping bolt securely. Recheck
timing, to ensure retightening has not disturbed
distributor position.
10.Refit vacuum hose.
11.Disconnect stroboscopic timing lamp and
tachometer from engine.

ELECTRICAL
1
REPAIR FUSE BOX - INTERIOR
Right Hand Drive shown
The interior fusebox is fitted below the steering column, behind the trim panel. It comprises of three integral units.
'A'Main fusebox,'B'Satellite 2,'C'Satellite 1.
A label in the fusebox cover shows the circuits protected, the fuse rating and their locations. Access is by
releasing the fixing screws and lowering the panel.
'A' Main fusebox
1. Stop lights, direction indicators
2. LH side light
3. Radio/cassette/CD player
4. RH headlight main beam
5. LH headlight main beam
6. Cigar lighter
7. Airbag SRS
8. RH side lights
9. Rear fog guard lights
10. RH headlight dipped beam
11. LH headlight dipped beam
12. Multi-function unit
13. Ignition feed for Multi-function unit
14. Instruments, reversing lights
15. Air conditioning, windows
16. Washers & wipers - front
17. Starter, glow plug
18. Wash/wipe - rear, mirrors, cruise control
'B' Satellite 2
1. Electric windows - front
2. Electric windows - rear
3. Anti-lock braking
4. Central door locking
5. Electric sun roof
6. Trailer lights
'C' Satellite 1
1. Anti-theft alarm
2. Headlight washers
3. Engine management
4. Anti-lock brakes
5. Anti-theft alarm
6. Rear air conditioning, heater
'D' Spare fuses (5 off)

86ELECTRICAL
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REPAIR FUSE BOX - ENGINE COMPARTMENT
The fusebox is located on the right side of the engine compartment. The circuits protected and their locations are
shown on the inside of the fusebox cover. To change a main circuit fuse prise off protective cover A and remove
retaining screws.
Fuses
1. Heated rear window
2. Sidelights
3. Air conditioning
4. Hazard warning lights, horn
5. ABS valve
6. Fuel pump
7. Fuel injectors
A Main circuit fuses
8. ABS pump
9. Ignition circuits
10. Lighting
11. Window lift, central door locking, rear blower
12. Heater, air conditioning
13. Generator