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Re: More data on glowing ignition light

To: Joe Whalley <jw@mail09.mitre.org>
Subject: Re: More data on glowing ignition light
From: Reed Mideke <rmideke@interbase.com>
Date: Tue, 22 Sep 1998 09:33:27 -0700
Joe Whalley wrote:
> 
> The light glows brightly when I turn the ignition on, then dims, but does not
> go out when the engine starts. The voltage on the battery with engine off is
> 12.5, goes up to 13.6 at 3000 RPM. It seems the alternator is charging. Maybe
> the indicating circuit is faulty? Where is the voltage regulator on a 72 Mk4?
> Could it need a little adjustment to get the charging voltage up around 14?
> 
> Joe
Joe,

I think all the spit alternators have internal regulators with
no user servicable parts (someone correct me if I'm wrong, I'm
going from memory here) The light can indicate either an
undercharge or overcharge. The regulator on mine died, causing
it to produce up to 17 volts at 6K rpm. The light would get
increasingly bright with RPMs, and the tach would wig out.
Overcharging is bad for your battery, since it makes it boil over
(which is bad for your paint too).
Now, (with a new alternator + regulator) the light comes on dimly
just after starting, and goes out after about a minute.
13.6  might be a little bit low, but I'd just carry jumper cables
and not worry about it. Make sure your alternator and battery
connections are clean.

Good luck.
-- 
Reed Mideke                                        rmideke@interbase.com

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