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Rotating Electrics: Common Issues

By autotech-nath on May 23, 2022

Starters and alternators have never been so important, to ensure the multiple engine starts required on start/stop equipped vehicles) technology and to sufficiently charge the battery and support the power hungry electrical systems. The diagnoses of faults and using quality replacement units is therefore a necessity for the modern independent workshop. Here, Hella outlines some common problems and issues to look out for.


There are several common symptoms that may indicate a fault in the starter, such as no response when actuating the ignition switch: the starter ‘clicks’ but does not engage or it audibly turns without the motor engaging with the flywheel.

A starter malfunction can have different causes, including a faulty electrical connection, the solenoid switch (engaging relay) is stiff or defective, the electric motor is broken or the single- pinion gear, starter pinion or freewheel have been damaged. Battery voltage may also be a factor to consider and/or loose (high resistant) connections.

Dependent on the problem, technicians should look at the starter and decide if it needs to be replaced. It must also be noted that some vehicles have inherent faults such as ignition switch failure, which again can cause problems with the starter.


Symptoms for a faulty alternator can include the charging indicator warning light coming on, starting difficulties due to an insufficiently charged battery, the battery becomes too hot due to charge overload, the headlights get brighter or dimmer in relation to the engine speed or the bulbs burn out more quickly than normal.

Alternator malfunction is not always due to an internal fault, such as a faulty winding, rotor, rectifier, or control unit. So, before replacing the alternator, additional components should be considered as a cause and checked. The cause may be because of a poor performing battery, corrosion or loose electrical connections causing high resistance to the alternator, loose/faulty auxiliary belt or the belt tensioner being too loose or over-tight.

If, after the checks have been made, the unit does need replacing, it’s always best practice to fit an OE quality component. The HELLA core-free programme now encompasses 1,240 references and simplifies life for both workshops, and the wholesalers supplying them, as it dispenses with the need for either party to return the faulty unit and comes without the complication of a surcharge. As a result, neither has to deal with a complicated payment process. Recent additions to the range include starters for applications such as the Audi Q5 and SQ5 TFSI, BMW 2 Series Coupe, Mercedes S-Class and MINI Cooper D, alongside alternators for the Honda Jazz III and KIA RIO III.



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Autotechnician is a magazine published nine times a year, delivering essential information to independent garage owners and technicians in the UK. Delivered both digitally and in print, autotechnician provides readers with technical, training, business advice, product and news, allowing our readers to keep up to date with information they need to run and work within a modern workshop.
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