ALTERNATORS: Fault finder check list
Problem: Warning light remains on
Possible causes:
1. Check the fan belt is not slipping
2. Check the positive and negative supply to the alternator
3. Ensure warning light circuit is not down to earth
4. Suppressor fitted incorrectly
5. Terminals on alternator and/or wiring burnt
Problem: No warning light
Possible causes:
1. Check bulb has not blown
2. Poor or burnt connectors to alternator
3. Break in warning light circuit wiring to instruments
4. Check ignition fuse for instrumentation
Problem: Alternator undercharging
Possible causes:
1. Slipping fan belt
2. Poor earth to alternator
3. Poor supply to alternator
General Checks:
1. Ingress of oil burns out the alternator
2. Over tightened fan belt bearings become noisy
3. Wrong spacers on pulley
4. Brackets broken
STARTER MOTORS: Fault finder check list
Problem: Starter will not turn
Possible causes:
1. Poor connections to starter
2. Check positive and negative supply to starter
3. Less than 12V to solenoid exciter terminal due to worn ignition switch or broken wiring
4. Flat battery
Problem: Starter turns slowly or makes grating noise
Possible causes:
1. Vehicle timing out of specification
2. Poor supply to starter
3. Gearbox bush worn on free floating starter
4. Poor engine earth
Problem: Starter motor sticks
Possible causes:
1. Excessive clutch dust on starter
2. Worn ring gear on car
3. Ignition switch sticking and not returning
Quick test: Place starter tightly in a vice. Use a 12V battery and jump leads. Connect negative side to starter body and positive to main feed on starter. With an insulated screwdriver arc across the main feed and solenoid exciter terminal. Starter should throw in and turn at speed.
Technical help from Autoelectro
Autoelectro’s website ‘catalogue’ section lists specific technical information for many applications. All you have to do is click on the red ‘i’ that accompanies the product specifications.
