1. Make sure the alternator drive belt is normal.
If the above steps do not bring results, we recommend that you entrust the subsequent generator check to a workshop. If you perform further troubleshooting on your own, you need to be especially careful and attentive so as not to mix up the terminals when connecting the measuring device. In this case, complete damage to the generator cannot be ruled out.
2. Connect a voltmeter to both battery terminals and start the engine.
3. Increase the engine speed and simultaneously monitor the voltmeter readings. As soon as the voltmeter shows a voltage within 13.5-14.8 V, leave the engine running at the speed at which this voltage is shown and turn on the maximum possible number of on-board network consumers. The battery voltage should remain within the specified values. If it changes, then the voltage regulator is most likely faulty or the generator brushes are worn out. If the voltmeter registers too high a battery voltage, then the rectifier diodes are burnt out.
If the inspection reveals that the generator is faulty, it can be removed and delivered to a workshop for repair. We do not recommend repairing the generator or voltage regulator yourself unless you have sufficient experience. If such a service is offered, the workshop can exchange the removed generator for a repaired one of the same model. Minor repairs to the generator, such as replacing carbon brushes, can be performed in an electrical equipment repair workshop.
(Source of the article is website peugeotbook)
The generator is equipped with bearings that are lubricated for the entire service life and therefore do not require maintenance. The outer surface of the generator housing should be kept clean, preventing the ingress of water or solvents.
Carbon brushes operate on contact rings and therefore their service life is quite long. If you suspect that the cause of the generator power loss may be carbon brushes, it is recommended to contact an electrical repair shop.