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/engine unit 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.
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]
If wiper motor doesn't work [what's 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]
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.
(To see previous homepages visit the Homepage Archives link)