1996 LAND ROVER DEFENDER Workshop Manual

ELECTRICAL
1
FAULT DIAGNOSIS GENERAL INFORMATION
Detailed information of electrical systems, component
locations and circuit diagrams are covered in the
Defender Electrical Troubleshooting Manual.
This section covers checks of the charging 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 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 or exteriorlamps.
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 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.

ELECTRICAL
1
REPAIR ELECTRICAL PRECAUTIONS
The following guidelines are intended to ensure the
safety of the operator whilst preventing damage to
electrical and electronic components fitted to the
vehicle.
Polarity
Never reverse connect the vehicle battery and always
observe the correct polarity when connecting test
equipment.
High voltage circuits
WARNING: Before commencing work on
an ignition system, all high tension
terminals, adaptors and diagnostic
equipment for testing should be inspected to
ensure that they are adequately insulated and
shielded to prevent accidental personal contacts
and minimize the risk of shock. Wearers of
surgically implanted pacemaker devices should
not be in close proximity to ignition circuits or
diagnostic equipment.
Whenever disconnecting live high tension circuits
always use insulated pliers and never allow the open
end of a high tension lead to come into contact with
other components particularly electronic control units.
Exercise caution when measuring the voltage on the
coil terminals while the engine is running, since, high
voltage spikes can occur on these terminals.
Connectors and harness
Always ensure that these items are dry and oil free
before disconnecting and connecting test equipment.
Never force connectors apart either by using tools or
by pulling on the wiring harness. Always ensure
locking tabs are disengaged before removal and note
orientation to enable correct reconnection. Ensure that
any protective covers and substances are replaced if
disturbed. Having confirmed a component to be faulty
switch-off the ignition and disconnect the battery.
Remove the component and support the disconnected
harness. When replacing the component keep oily
hands away from electrical connection areas and
push connectors home until any locking tabs fully
engage.Battery disconnecting
Before disconnecting the battery, switch off all
electrical equipment.
Battery charging
Recharge the battery out of the vehicle and keep the
top well ventilated. While being charged or
discharged, and for approximately 15 minutes
afterwards, batteries emit hydrogen gas which is
flammable. Always ensure any battery charging area
is well ventilated and that every precaution is taken to
avoid naked flames and sparks.
GENERAL PRECAUTIONS
Switch-off ignition prior to making any connection or
disconnection in the system as electrical surge
caused by disconnecting 'live' connections can
damage electronic components.
Ensure hands and work surfaces are clean and free of
grease, swarf, etc. as grease collects dirt which can
cause tracking or high-resistance contacts.
When handling printed circuit boards, treat them as
you would a disc - hold by the edges only.
Prior to commencing a test, and periodically during a
test, touch a good earth, for instance, a cigar lighter
socket, to discharge body static as some electronic
components are vulnerable to static electricity.

86ELECTRICAL
2
REPAIR BATTERY
Service repair no - 86.15.01
NOTE: If the vehicle is fitted with a battery
backed-up alarm sounder, disconnecting
the vehicle battery will cause the alarm to
sound unless the following procedure is followed:
1.Remove LH front seat cushion.
2.Release retaining clip and remove battery
access cover.
3.Slacken battery negative lead clamp bolt.
4.Turn starter switch 'on'.
5.Turn starter switch 'off' and remove key.
6.Disconnect battery WITHIN 15 SECONDS.
If alarm is accidentally activated, ensure sounder is
connected and silence by turning the starter switch to
position 'II'.Remove
WARNING: During battery removal or
before carrying out any repairs or
maintenance to electrical components
always disconnect negative lead first. If positive
lead is disconnected with negative lead in place,
accidental contact of a wrench to any grounded
metal part could cause a severe spark, possibly
resulting in personal injury. Upon installation of
battery always connect positive lead first.
1.Remove LH front seat cushion.
2.Release retaining clip and remove battery
access cover.
3.Disconnect both battery leads, negative first.
4.Slacken securing nuts and move battery clamp,
with 'J' bolts aside.
5.Remove battery.
NOTE: Coat battery clamps and terminals
with petroleum jelly before refitting.
Refit
6.Position battery and secure with clamp. Ensure
'J' bolts are hooked correctly under retaining
brackets on base of battery box.
7.Reconnect battery leads, positive lead first.
8.Fit battery access cover.
9.Fit seat cushion.

ELECTRICAL
3
REPAIR ELECTRONIC CONTROL UNIT (ECU)
Service repair no - 86.55.85
Remove
1.Remove LH front seat cushion.
2.Release retaining clip and remove battery
access cover.
3.Slacken battery negative lead clamp bolt.
4.Turn starter switch 'on'.
5.Turn starter switch 'off' and remove key.
6.Disconnect battery negative lead.
NOTE: Operation 6 needs to be carried out
within 15 seconds to avoid activating
battery backed-up alarm sounder, if fitted.
7.Remove steering wheel
See STEERING,
Repair, Steering wheel.
8.Remove 4 screws securing instrument panel to
fascia cowl
See INSTRUMENTS, Repair,
Instrument panel.
9.Pull instrument panel away from fascia cowl and
disconnect speedometer cable, multi-plugs,
alarm LED plug lead, heated rear screen lead,
gearbox oil temperature lead and immobiliser
warning light leads.
10.Remove instrument panel.
11.Remove 2 screws securing ECU to fascia cowl
(LH drive shown). On RH drive vehicles ECU is
positioned lower down, on vertical face of fascia
panel.
12.Release ECU from fascia cowl and disconnect
both multi-plugs.
13.Remove ECU.
NOTE: A new ECU must be initialised
using TestBook.
Refit
14.Position ECU at fascia cowl and reconnect both
multi-plugs.
15.Locate ECU on mounting face of fascia cowl and
secure with 2 screws.
16.Position instrument panel to fascia cowl and
reconnect immobiliser warning light leads,
gearbox oil temperature lead, heated rear screen
lead, alarm LED plug lead, multi-plugs and
speedometer cable.
17.Secure instrument panel to fascia cowl with 4
screws
See INSTRUMENTS, Repair,
Instrument panel.
18.Fit steering wheelSee STEERING, Repair,
Steering wheel.
19.Reconnect battery negative lead.
20.Fit battery access cover.
21.Fit LH seat cushion.

86ELECTRICAL
4
REPAIR HANDSET BATTERY
Service repair no - 86.77.13
Remove
1.Unlock vehicle and disarm alarm system.
2.Turn starter switch to position 'II'.
3.Turn starter switch back to position '0' and
remove key.
4.Carefully prise handset apart, starting from
keyring end, using a coin or small screwdriver.
5.Slide battery out from retaining clip.
6.Press and hold one of the handset buttons for at
least five seconds to drain any residual power
from handset.
NOTE: The engine will immobilise five
minutes after key is removed from starter
switch.Refit
7.Fit new battery into handset retaining clip with
positive side uppermost. Finger marks will
adversely affect battery life; if possible, avoid
touching flat surfaces of battery and wipe clean
before fitting.
8.Reassemble two halves of handset.
9.Press RH (Padlock) button at least four times
within range of vehicle to resynchronise handset.
10.Check operation of alarm system.
WARNING: The handset contains delicate
electronic circuits and must be protected
from impact and water damage, high
temperatures and humidity, direct sunlight and
effects of solvents, waxes and abrasive cleaners.
NOTE: New handsets must be be
initialised using TestBook.

ELECTRICAL
5
REPAIR PASSIVE COIL
Service repair no - 86.77.35
Remove
1.Remove LH front seat cushion.
2.Release retaining clip and remove battery
access cover.
3.Slacken battery negative lead clamp bolt.
4.Turn starter switch 'on'.
5.Turn starter switch 'off' and remove key.
6.Disconnect battery negative lead.
NOTE: Operation 6 needs to be carried out
within 15 seconds to avoid activating
battery backed-up alarm sounder, if fitted.
7.Remove steering wheel
See STEERING,
Repair, Steering wheel.
8.Remove 4 screws securing instrument panel to
fascia cowl
See INSTRUMENTS, Repair,
Instrument panel.
9.Pull instrument panel away from fascia and
disconnect speedometer cable, multi-plugs,
alarm LED plug lead, heated rear screen lead,
gearbox oil temperature lead and immobiliser
warning light leads.
10.Remove instrument panel.
11.Remove 7 screws securing upper and lower
halves of nacelle to steering column mounting
bracket
See STEERING, Repair, Steering
column nacelle.
12.Release multi-switch gaiters from both sides of
nacelle.
13.Remove nacelle upper and lower halves from
steering column; collect blanking grommet from
RH side.
14.Disconnect multi-plug and remove passive coil
from starter switch.
Refit
15.Feed passive coil plug lead into fascia cowl area
and reconnect multi-plug .
16.Fit coil on starter switch.
17.Position nacelle upper and lower halves to
steering column mounting bracket and secure
with 7 screws. Do not fully tighten screws at this
stage
See STEERING, Repair, Steering
column nacelle.
18.Check that passive coil is still fitted correctly on
starter switch.
19.Check fit of nacelle at starter switch and steering
column and fully tighten fixing screws.
20.Fit multi-switch gaiters to both sides of nacelle
and check that blanking grommet is located.
21.Position instrument panel to fascia cowl area
and reconnect immobiliser warning light leads,
gearbox oil temperature lead, heated rear screen
lead, alarm LED plug lead, main harness multi-
plugs and speedometer.
22.Secure instrument panel to fascia cowl with 4
screws
See INSTRUMENTS, Repair,
Instrument panel.
23.Fit steering wheelSee STEERING, Repair,
Steering wheel.
24.Reconnect battery negative lead.
25.Fit battery access cover.
26.Fit LH seat cushion.
27.Test immobilisation and alarm system.

86ELECTRICAL
6
REPAIR IMMOBILISATION SPIDER
Service repair no - 86.77.03
Remove
1.Remove LH front seat cushion.
2.Release retaining clip and remove battery
access cover.
3.Slacken battery lead clamp bolts.
4.Turn starter switch 'on'.
5.Turn starter switch 'off' and remove key.
6.Disconnect battery leads.
NOTE: Operation 6 needs to be carried out
within 15 seconds to avoid activating
battery backed-up alarm sounder, if fitted.
7.Remove battery clamp and 'J' bolts.
8.Remove 4 nuts securing immobilisation spider
housing box to fixing studs on front face of
battery box.
9.Remove grommet securing spider harness to
corner face of battery box.
10.Carefully pull harness into battery box, lift spider
housing box and place on front edge of seat
base.
11.Using a suitable sheet to protect inside of
vehicle, grind heads off 6 monobolts securing lid
to spider box housing.
12.Detach lid from housing and disconnect spider
harness plug.
13.Unscrew two nuts and remove immobilisation
spider from lid studs.
NOTE: If spider box lid and/or sealing
gasket is damaged during operation 11 a
new lid will need to be fitted.
NOTE: A new immobilisation spider must
be initialised using TestBook.
Refit
14.Fit immobilisation spider onto lid studs and
secure with retaining nuts.
15.Reconnect harness plug to spider and ensure it
fully 'clicks' home.
16.Position lid and spider assembly into box
housing so that harness plug is furst away from
harness entry.
17.Secure lid to spider box housing with monobolts.
18.Refit harness grommet into spider box, if
disturbed on removal procedures, and ensure
harness covering is fully inserted through
grommet to make water tight seal.
19.Push excess harnes cable through corner face
of battery box and fit grommet.
20.Fit spider housing box to fixing studs and secure
with four nuts.
21.Fit 'J' bolts and clamp to secure battery,
22.Reconnect battery leads.
23.Fit battery access cover.
24.Fit LH seat cushion.
25.Test immobilisation and alarm system.

ELECTRICAL
7
REPAIR BONNET SWITCH
Service repair no - 86.55.89
Remove
1.Disconnect bonnet switch harness multi-plug.
2.Release harness retaining clip from switch
mounting bracket.
3.Press in retaining clips and remove switch from
mounting bracket.
Refit
4.Insert harness multi-plug and bonnet switch into
mounting bracket. Push switch firmly down to
secure in position.
5.Connect harness multi-plug.
6.Fit harness retaining clip in mounting bracket.ULTRASONIC SENSOR
Service repair no - 86.77.32
Remove
1.Carefully prise ultrasonic sensor from cantrail
trim.
2.Disconnect harness plug and remove sensor.
NOTE: Position of sensor will change
according to vehicle type.
Refit
3.Connect harness plug to sensor.
4.Fit sensor to cantrail trim.