Thanks to the help of many listers, I believe I've eliminated my battery
draining short. It looks like the culprit was the new GM alternator and the
cure was adding a diode to the circuit.
There was something odd about this that I still don't understand: I was
originally troubleshooting by testing voltage between the negative post and
ground with a voltmeter. What I found confusing was that when I removed the
alternator plug the voltage dropped from 12 to 10 volts -- not to zero. Then I
started testing with a light and the light reliably went out when the plug was
removed and testing afterwards with the voltmeter yielded no voltage. Its
almost as if there's a capacitor somewhere else in the circuit that's storing
the leaking current and the voltmeter doesn't draw it down, but the light does.
At any rate, I've installed the diode and both my test light and voltmeter show
no current. I'm out of town for a week so the 6'll be sitting in the garage
with the battery connected and if it fires up next Saturday, this problem will
be a distant memory.
Dwayne
'74
-----Original Message-----
From: Stephen Hanselman [mailto:tr6@kc4sw.com]
Sent: Thu 4/17/2003 7:34 AM
To: 6pack@autox.team.net
Cc:
Subject: RE: Chasing a short
Hi All,
I've been watching this thread from afar, my connection
would not allow replies, and have the following observations.
1. The ignition circuits can not be involved IF they go
through the ignition switch. the coil/points are switched
off by the key switch. You can prove that by watching
the Ammeter on the dash as you turn on the key switch.
The draw is fairly high.
2. the most likely paths would be any switched circuit.
The switch contact(when off) still has a high resistance
connection to the "on" position. I suspect you'll find a switch
that is allowing enough current to flow through a lamp but
the flow level is to low to light the lamp.
3. I know that the alternator has been replaced but it is still
a possible fault. It is one of the things that is across the
battery at all times.
To troubleshoot this problem I'd hook an Ammeter, capable
of low current level measurements, in series with the battery.
Then go to the fuse block and start pulling fuses ( of course
this assumes you see current flow with everything turned off).
There are two theories in troubleshooting, one is to remove
stuff until the problem goes away the other is to remove, observe,
and then replace. I think doing the first and then the second
might be needed here. Using the wiring diagram for the car isolate
each circuit by unplugging it.
Happily the TR6 is no where near as complex as a more modern
computer(ugh) controlled car. Also happily a TR6 draws NO current
when it is shut off, so ANY flow indicates a problem.
If you want I'll look at it closer when I get home.
Regards,
Steve
tr6@kc4sw.com
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