Error: Generator does not start, no generator charging indicator light appears when the ignition is switched on. The connection of the positive line to the generator has been checked and is free of defects, as is the free-running of the alternator.
Remove the engine cover, on the left side (driver's side) at the bottom, near the radiator. There is a clutch station there, and the cable for the alternator's excitation is also routed through there. These very thin cables often break exactly at this point. Ideally, repair with an extended cable and 2 weldable crimp connectors.
If the problem persists or if the cable was not broken and no indicator light is illuminated, replace the alternator.
TIP: Get the alternator from the salvage yard, alternators that are the same as Golf IV engines are suitable! If the alternator does not fit into the bracket on the engine block, because the two integrated bushes are too tight, push a through-hole from the side (from the ribbed side) and gently press the threaded bolt 1-2mm outwards - in some used alternators, these bolts have shifted slightly and the alternator does not fit in.
EDIT by DBär: See also:
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