If you had a diode and the warning light came on as you turned on the
ignition and the diode stopped the warning light glowing when a load was
switched on, then that indicates the voltage was higher in the charging
circuit than the ignition circuit and indicates a poor connection between
them.
The whole point is, if everything is working correctly you don't need a
diode, you won't get dim and flickering warning lights and you won't get the
engine running on.
These cars didn't come out of the factory needing diodes, so to put them in
now is a cheap frig.
PaulH.
-----Original Message-----
From: Florrie & Allen Bachelder <bachldrs@swva.net>
To: Paul Hunt <paul.hunt1@virgin.net>
Cc: mgs@autox.team.net <mgs@autox.team.net>
Date: 11 February 1999 00:48
Subject: Alternator light
>>...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
>
>
|