Date: Mon, 8 May 2000 19:17:57 -0400
Reply-To: David Beierl <dbeierl@IBM.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Beierl <dbeierl@IBM.NET>
Subject: Re: 84 westy alternator light flickers(longish)
In-Reply-To: <60F1FEB31CA3D211A1B60008C7A45F4302489675@blaze.bcsc.GOV.BC .CA>
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At 18:50 5/8/2000, Johnson, David R FOR:EX wrote:
>Hello Volks,
>
>Here's the deal, Yesterday when going for a relaxing Sunday drive, about 10
>km in, the alternator light in the dash comes on. EEEk.
Ok, this means that the line going from the LED to the D+ terminal on the
alternator is being grounded. The usual reason is that the alternator is
not charging.
> Now, this light has
>ALWAYS come on when the engine turns over, then when it is running a "blip"
>of the throttle and its gone. I read some discussion lately about how this
>is not normal, I though PPff, whatever, it has always done this and never
>posed a problem to date.
Well, VW says it's normal. My van has always done it, both before and
after alternator rebuild and with different regulators including the
brand-new Hella one I just got from Ken Wilford.
> There has never been a problem with cranking
>power. I also have an auxiliary Optima that is connected to the LED. This
>light has recently been in the yellow unless the engine is running,
>alternator charging. In the not to distant past this light was always in
>the green, unless there was a power draw. Hmmm . I believe the consensus was
>that this was normal, to be in the yellow.?
If your battery is fully charged, the light should be green when there are
no drains on the battery. However it does not take very much discharging
to bring the light to yellow, especially while the battery is in use.
> The alternator light seams to come on and go off intermittently, and around
>4000rpm it also goes out. The belts are tight, with the engine running, the
>LED for the auxiliary battery is in the green. So I assume the alternator
>is functioning.
Uh...why? The LED is put there to tell you that the alternator is not
functioning. It may be wrong, but that's what it's telling you.
> Excuse my ignorance here, I am no mechanic. Is there a way
>to test the alternator.,
The best way for a full test is to take it to an auto-electric shop or a
parts place with a tester.
A quick test is to check the voltage between the battery posts (not the
terminals clamped to the posts) while the engine is running and after you
have blipped the throttle to start the alternator charging. It should be
distinctly over 13 volts. Then check between the body and the alternator
output terminal, or better yet between the negative battery post and the
alternator terminal. It should be only slightly higher than the previous test.
In any case, while the LED is lit, check the voltage at the alternator D+
terminal -- if at this time it is near ground, the alternator definitely
has a problem. If it's near the output voltage but the LED is still lit,
that suggests a problem in the wiring.
>I am thinking perhaps there is a short somewhere on the auxiliary battery
>side, causing the LED to dip into the yellow, causing the alternator to work
>harder, and it has just decided it is too much(?) Does this sound
>reasonable?
No. You're working too hard. Start with the likelihood of a bad
alternator, eliminate that and then if necessary look for other things. If
there were a short in either of your batteries you would probably have
already had a battery explosion or melted wiring or blown fuse or even a
fire of some sort.
>I assume I need to measure battery voltage(auxiliary), while pulling fuses,
>watching for any change in voltage, thereby isolating possible causes of
>power draw( if any exists(?))
solution, so whatdoyathink?? Do I need to buy the 350 dollar alternator,
>what about rebuilt. Any and all advise appreciated. TIA
My experience with rebuilt alternators has been good. When my Vgon
alternator failed I had it rebuilt by a local shop that does a lot of
Bosch. They charged about US$100.
david
David Beierl - Providence, RI
http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"
