[Technology] Ask NSC: Alternator knackered, or...

[beorhthelm]

i have an odd problem with car, MKIV Golf showing a battery light. testing with multimeter it shows 12.1 V when started this stays continuous, slight drop and the my assumption is the alternator is knackered. however, when i tested again this morning before taking to garage to check, it showed 14.4V running. got to the garage, no warning light but that came on while waiting for them to open. came back and chaps verdict was bad alternator, with the voltage back to showing 12.x V off or while running.

so while alternator is still number one suspect, it appears not charging when the engine has warmed up. is this some electonics detecting another fault (protecting over charge) and disconnecting the charge, lose something somewhere, or just daft redherring and change the alternator?

over to NSC.

 

[Tim Over Whelmed]

I'd switch it off and back on again (sorry, you've now exhausted my vehicle mechanics knowledge)

 

[beorhthelm]

I'd switch it off and back on again (sorry, you've now exhausted my vehicle mechanics knowledge)

this has been done several times.

 

[blue'n'white]

BG will have a friend who can fix it . . .

 

[RandyWanger]

Maybe the voltage regulator that's busted if it's not the alternator.

 

[beorhthelm]

Maybe the voltage regulator that's busted if it's not the alternator.

that would be my hope and a lot less cost, though i gather you have to remove the alternator to change the regulator so still pay about the same labour.

 

[upthealbion1970]

Could be alternator clutch pulley or belt slipping