Date: Wed, 10 Jan 2001 19:54:30 -0800
Reply-To: "MOST,DAVID" <most@UCLA.EDU>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: "MOST,DAVID" <most@UCLA.EDU>
Subject: Re: two red lights aren't on at start
In-Reply-To: <5.0.2.1.2.20010110221539.031edf98%#pop1.attglobal.net@192.168.0.1>
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Given your explanation below (thanks) and that I haven't check anything
yet, could the oxygen sensor be responsible for the symptoms? While
checking another problem the other day, I started the the engine with the
oxs disconnected. I then connected it while the engine was running
(though I only disconnected and connected the two wire plug and not the
single wire lead). I don't notice any new running problems.
Thanks again,
David
On Wed, 10 Jan 2001, David Beierl wrote:
> At 10:17 PM 1/10/2001, Bill Davidson wrote:
> >But wouldn't the alternator light come on after starting if it wasn't
> >charging? ... he said that it doesn't come on at all... I assume that means
> >after starting also...
>
> No, it wouldn't. The alternator needs a tickler circuit to get it started
> -- that's the D+ terminal which must be supplied with a small 12v current
> to begin charging, and which then itself supplies 12v while the alternator
> is charging.
>
> Having the dual need of a startup circuit and also a warning light for the
> alternator, the auto-makers combined the two -- when the alternator is
> drawing through the D+ terminal the light is on, and when it's supplying
> voltage there the light goes out. The current through an LED isn't enough
> to trigger the alternator, so VW also put a resistor in parallel with the
> LED through which most of the current flows -- might be 150 ma or something
> like it.
>
> Then because they also needed a lamp test for the OXS light (and safety
> belt light, I think?) they hooked those into the circuit as well, using
> diodes to isolate them. And oh yes, they use it to drive the relay to
> power the fridge when the alternator *is* charging.
>
> If the alternator light doesn't light with ignition on, it's one of three
> things: bad LED (happens, but you can win lots of money betting against
> it), bad 12v supply to the panel (which ought to affect other things on the
> panel), or the other end of the circuit isn't being properly grounded
> through the alternator -- busted wire, unplugged wire, bad connection at
> the panel plug, bad alternator. But regardless, if it doesn't light with
> the motor off it won't light with the motor on either.
>
> david
>
>
> >Bill
>
> David Beierl - Providence, RI
> http://pws.prserv.net/synergy/Vanagon/
> '84 Westy "Dutiful Passage"
> '85 GL "Poor Relation"
>
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