The battery charge indicator light does not light when the ignition is on
The battery is discharged
Charge the battery.
The battery terminals are loose or the terminals are rusty
Check the wire fastening, clean the terminals and tighten the bolt.
The generator wire terminal has become loose or the terminals have become rusty
Check the wire fastening, clean the terminals and tighten the nuts.
The battery charging indicator light has burned out
Replace the light bulb.
The voltage regulator is faulty
Check the voltage regulator. Replace if necessary.
Open circuit between generator, ignition switch and indicator light
(Text republished from the website: mercedesman.ru)
Check the circuit with an ohmmeter. If necessary, restore the circuit or replace the wire.
Carbon brushes do not fit into the slip ring
Check the ease of movement of the brushes in the holder, as well as the elasticity and clamping force of the brush springs.
Battery charge indicator light does not go out when engine speed increases
The V-belt is loose or slipping
Check the condition of the V-belt and tensioner. Replace the belt if necessary.
Wear of voltage regulator carbon brushes
Inspect the carbon brushes. Replace if necessary.
Poor contact between the generator and the voltage regulator
Check the wires and contacts. Replace the wiring harness if necessary.