Fault finding - electrical system, 9•14 electrical system, No voltage at starter motor – FIAT Uno 45 User Manual

Page 103: Voltage at starter motor - faulty motor, Starter motor noisy or rough in engagement, Alternator not charging, Fuel gauge gives no reading, Fuel gauge registers full all the time, Horn operates all the time, Horn fails to operate

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9•14 Electrical system

Fault finding - electrical system

No voltage at starter motor

Battery discharged

Battery defective internally

Battery terminals loose or earth lead not securely attached to body

Loose or broken connections in starter motor circuit

Starter motor switch or solenoid faulty

Voltage at starter motor - faulty motor

Starter brushes badly worn, sticking, or brush wires loose

Commutator dirty, worn or burnt

Starter motor armature faulty

Field coils earthed

Starter motor noisy or rough in engagement

Pinion or flywheel gear teeth broken or worn

Starter drive main spring broken

Starter motor retaining bolts loose

Alternator not charging*

Drivebelt loose and slipping, or broken

Brushes worn, sticking, broken or dirty

Brush springs weak or broken

* If all appears to be well but the alternator is still not charging, take the
car to an automobile electrician for checking of the alternator

Ignition light fails to go out, battery runs flat in a
few days

Drivebelt loose and slipping, or broken

Alternator faulty

Battery will not hold charge for more than a few
days

Battery defective internally

Electrolyte level too low or electrolyte too weak due to leakage

Plate separators no longer fully effective

Battery plates severely sulphated

Drivebelt slipping

Battery terminal connections loose or corroded

Alternator not charging properly

Short in lighting circuit causing continual battery drain

Fuel gauge gives no reading

Fuel tank empty!

Electric cable between tank sender unit and gauge earthed or loose

Fuel gauge case not earthed

Fuel gauge supply cable interrupted

Fuel gauge unit broken

Fuel gauge registers full all the time

Electric cable between tank unit and gauge broken or disconnected

Horn operates all the time

Horn push either earthed or stuck down

Horn cable to horn push earthed

Horn fails to operate

Blown fuse

Cable or cable connection loose, broken or disconnected

Horn has an internal fault

Horn emits intermittent or unsatisfactory noise

Cable connections loose

Horn incorrectly adjusted

Lights do not come on

If engine not running, battery discharged

Light bulb filament burnt out or bulbs broken

Wire connections loose, disconnected or broken

Light switch shorting or otherwise faulty

Lights come on but fade out

If engine not running, battery discharged

Lights give very poor illumination

Lamp glasses dirty

Reflector tarnished or dirty

Lamps badly out of adjustment

Incorrect bulb with too low wattage fitted

Existing bulbs old and badly discoloured

Electrical wiring too thin not allowing full current to pass

Lights work erratically, flashing on and off,
especially over bumps

Battery terminals or earth connections loose

Lights not earthing properly

Contacts in light switch faulty

Wiper motor fails to work

Blown fuse

Wire connections loose, disconnected or broken

Brushes badly worn

Armature worn or faulty

Field coils faulty

Wiper motor works very slowly and takes
excessive current

Commutator dirty, greasy or burnt

Drive spindle binding or damaged

Armature bearings dry or unaligned

Armature badly worn or faulty

Wiper motor works slowly and takes little current

Brushes badly worn

Commutator dirty, greasy or burnt

Armature badly worn or faulty

Wiper motor works but wiper blade remains static

Drive spindle damaged or worn

Wiper motor gearbox parts badly worn

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