Alternator Woes.... Again

[wolfgang]

I fitted a new ( refurbished )alternator just over a year ago and it is knackered already. Have I just been unlucky and got a duff one or is there something more fundamental wrong with wiring. The alternator I fitted had an internal regulator and the wiring on the bus bypasses the external regulator so this part seems ok. The idiot light started coming on and going off a couple of weeks ago but when I tested with a multimeter if showed if was charging ok. Yesterday after a longish drive when I turned the ignition on the light was off. When I checked with a multimeter today it is showing that the battery is not charging. The battery is new so that ruled out that side of things.

 

[CornishSilver]

Id check the output voltage on the alternator with the plug disconnected, I had a crappy connection on my plug and the spade would slip up as I plugged it in, may be worth a look

 

[wolfgang]

^^ sorry being a bit dim. Do I just put the positive prong of the multimeter to the output and the negative to earth ?

 

[CornishSilver]

I never had to find out myself as I saw the problem without needing to suss it out. I would have thought you would go across the terminals but going to earth should work but will maybe show 6-7v rather than 12-14.6v? This may help before you have a poke about http://www.vw-resource.com/alternator_generator.html

 

[alikat]

Chinese or Bosch alternator? You can still buy genuine Bosch voltage regulators if that turns out to be the problem. Bosch Brazil alternators are made from the last scrapings at the factory and are sometimes dead in the box! I bought one for $20 and a regulator swap cured it.