Allen, if the B is a 77 then the diode was probably put inline to stop
the car from running on after the key was removed.
...Art
On Wed, 10 Feb 1999, Florrie & Allen Bachelder wrote:
> >...Fitting a diode in the indicator lead to cure this is absolutely stupid -
> >all you are doing is stopping your alternator telling you when it has failed
> >completely, it would be far simpler to remove the light altogether. But the
> >preferred option is to fix the real problem.
> >
> >PaulH.
>
> Paul - and List -
>
> Maybe it is ...absolutely stupid... but I can duck that one 'cause I'm not
> the one who did it. At any rate, the offending diode is no longer there.
> But even then I ask why, when the diode was still there, did the light
> still come on brightly when switching on the ignition (as it is supposed
> to), only to promptly quit when the engine started (again, as it is
> supposed to)? Why did the diode not prevent it from lighting at all?
>
> As I think about this, I may be starting to answer my own question.
> Hopefully you can either verify or show me the error in my thinking. The
> light simply indicates a voltage desparity between alternator output and
> the ignition circuit, right? What if the alternator output voltage is
> slightly higher than that (from the battery) at the end of the white wire?
> The light would glow then too, right? But since that is not due to an
> alternator fault, we don't need that information. So, (1) can we defend
> that in-line diode on the basis that, since it allows current flow in one
> direction only, it is simply keeping the light off when the alternator
> output is greater than the ignition circuit, and (2) is there a type of
> battery defect that can lower its output enough to cause this problem (the
> glow is rpm-independent)? I would presume that if this is due to line loss
> from poor contact in a bullet connector or the ignition switch, that in 23
> years, total failure would have resulted.
>
> I suppose another answer that it apparently is charging - enough to be
> functional even - but not as much as it should. This battery, of
> indeterminate age when I bought the car in '91, still spins the starter
> faster than any of my other Bs.
>
> But really, despite the fact that we all know the light isn't supposed to
> glow, if the car is operated that way without electrical failure for over
> two years and perhaps 20,000 miles - mostly commuting at hours when the
> headlights are on - is it not unreasonable to presume that there is no real
> problem?
>
> Oh-oh - I should never talk that way - lest tomorrow morning I should go
> out to start my B and find the battery dead.
> TIA
>
> Allen
>
>
>
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