Land Rover
Series 1, 2 & 3 Electrical System - Fault Diagnosis
When looking for the cause
of an electrical fault in your Series Land Rover there are
some useful general principles to bear in mind.
1. Many electrical faults are caused by loose or corroded
connections.
2. Wires may also be chafed or broken and this often occurs
were they pass through the bodywork or are able to vibrate
when the Land Rover is in motion.
3. If the supply of current to the component is OK and the
return path to earth is OK then the fault lies in the component
itself.
4. An electrical test meter is the best aid to fault diagnosis
as it can test for current supply, circuit continuity
and condition of connections and wires. If a meter is not
available then a test lamp can be used made from a Land Rover
instrument panel bulb, holder and croc clips.
5. The principle of by-passing a suspect wire or component
using a wire and croc clips or test lamp is a useful procedure.
6. An electrical component which functions, but ineffectively,
is often due to a poor earth connection. Series Land Rovers
usually have the gearbox/engineunit earthed at a gearbox mounting.
[check for Series
Land Rover electrics in the tech section]
Battery not charging correctly
Loose or slipping fan belt; battery too old; worn dynamo/alternator
brushes or other internal fault; faulty voltage regulator.
If the light bulbs are burning out frequently and there is
a need to top up battery water regularly then the battery
is overcharging - in the case of an early Series Land Rover
then the regulator needs adjusting or replacing.
Lighting problems
If the brightness of lights (actually 'dimness' is more appropriate
for a Series model) varies with engine speed then check for:
loose or corroded earth connection to lights; battery discharged;
faulty voltage regulator; incorrect bulb fitted. If lights
flicker examine the circuits for loose connections (especially
earth). [check for Series Land Rover
headlamps in the tech section]
Starter motor [
If starter is noisy check mountings, wear on pinion
or flywheel teeth or worn starter bearings. If the engine
won't, turn check for loose, broken or dirty connections on
the battery, starter switch and starter. Could also be partially
ceased engine or discharged battery. Starter motor could have
faulty brushes, dirty commutator or starter pinion stuck in
flywheel mesh. A smart tap with a light hammer often reseats
loose brushes.[A Series Land Rover often perks up after light
tap with a hammer!] check for Series
Land Rover starter motors in the tech section]
Engine not firing
Faulty heater plug (diesel). Dirty or wrongly set spark plug
gaps; Damp ignition wiring or distributor cap. If there is
no spark at the contact points when ignition is ON and the
points are flicked open manually with a screw driver, then
there is a wiring fault in the low tension circuit.
Land Rover Engine misfires.
Check contact breaker, condenser and spark plugs.
[check for Series Land Rover distributor
in the tech section]
Common distributor faults
Points burnt or pitted; gap set incorrectly (0.36-0.4mm);
worn plastic points contact (drive shaft should be lightly
greased); cracked distributor gap; condenser faulty (test
by replacement); rotor arm pitted or burnt; weak or broken
contact breaker spring; excessive play in drive shaft due
to wear. [Note that electronic ignition is available for a
Series Land Rover]
Wipers
If wiper motor doesn't work [whats new? no early
Series model has proper wipers!] check for loose connections,
blown fuse or worn brushes in the motor. If the motor works
very slowly check for dirty commutator surface, worn armature
or dirty/misaligned bearings. If the motor works but blades
don't move check connection at wiper blade arm, otherwise
the wiper gearbox is faulty. [check for Series
Land Rover wipers in the tech section]
Horn
If horn sounds continuously check for horn push
button either stuck down or earthed. Otherwise the wire from
the button to the horn is damaged and earthed.
If the horn doesn't work then check for blown fuse or loose
wire or dirty connection. If the horn sounds intermittently
then the sound adjustment screw needs attention of there is
a loose wiring connection.
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