[Vwdiesel] Cont'd Electrical gremlins - bad ground?

[Nate Wall]

<<<Pretty sure the Diode Trio (bridge rectifier) is inside the alt.  I seem to
remember a problem with VW's and ALT lights, but can't remember what is was.
(I been out of the business for over 12 years now)>>>
\
Yes it is. They are in the back of the case. Problem was if the charge indicator
diode was out, the rotor coils never got excited to start charging, since the
excitation current went thru the diode.

--nate

W3wjr at aol.com wrote:

> --
> [ Picked text/plain from multipart/alternative ]
> What is the condition of the battery?  Remember Summer Kills them, but they
> seem last until the first time you really them, read cold.
>
> Plus the ALT light coming on.  Is the belt tight enough?  When you get the
> engine running, but the battery is low, it is demanding full output from the
> alt.  the Higher the RPM, the more the Alt can output (to a limit).  What I
> am getting at is the alt belt can be slipping at higher RPM when the alt is
> putting out its most current.  Try to turn the alt pulley by hand, if the
> belt is tight enough it will not allow you to turn the pulley in the belt.
> Not sure if a loose belt will turn on your ALT light though.
>
> Also a bad diode (or one breaking down under full current) will show the
> proper charging voltage, but the AC potential of the wave form will not
> charge the battery.
> Pretty sure the Diode Trio (bridge rectifier) is inside the alt.  I seem to
> remember a problem with VW's and ALT lights, but can't remember what is was.
> (I been out of the business for over 12 years now)
>
> Most garages will hook up the charging system tester for free, Its easy to
> do, and sells lots of batteries!
>
> Keep in mind, if you battery is good, but not fully charged, it will fail the
> load test and look like its bad.  Still, I believe if a battery is 4 or 5
> years old, you living on borrowed time anyway.  If a battery is $50.00,
> that's only $10.00 per year, cheep if you look at it that way.
>
> In a message dated 11/8/2002 7:47:50 AM Eastern Standard Time,
> hillsgrove at adelphia.net writes:
>
> > The problem is that my car is often losing the charge
> > >at the battery. Went out this morning and the battery is putting out about
> > >11.85 volts, not quite enough to crank it with a long glow plug cycle (I'm
> > >in Southern Maine, it's cold enough all ready at 6:45 AM)
> > >I had my alternator rebuilt at a  local shop a few weeks ago, so I'm going
> > >to assume it's okay now. The alternator light has been lit up recently
> > when
> > >the engine speed goes up before I shift, then it goes off.
> > <snip>
> > >The alternator is putting out the proper voltage when it's running (right
> > >around 13.9 volts). The battery is getting a proper charge when the car is
> > >running as well from my multimeter testing results. I had the battery
> > >tested and it is good according to the Autozone guy that tested it.
> > >
> >
> > <snip>
> > I'm suspecting it's just a really bad ground not
> > >allowing the battery to fully charge, but am not really sure. Any ideas?
> > >Thanks in advance.
> > >
>
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