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Subject:Can rain cause this problem? (electrical)
From:Victor Montgomery
Date:Sat, 30 May 1998 07:48:49 EDT

In a message dated 98-05-29 22:22:36 EDT, you write:

To: young@SHERLOCK.SIMS.BERKELEY.EDU

<<Today my '81 van died going westbound on the San Mateo bridge.  (Made
  it over the hump and drifted down the other side, for those familiar
  with the bridge!)>>

Normally vehicles do not 'die' while running unless the alternator ceases to
function. Note that an alternator will not charge a partially charged battery.
A generator will.

<<The battery died on me.  I knew I was having problems on the run up
  to the bridge; the wipers were slowing down, the radio was going in
  and out of tune, and turning on the lights made everything worse.
  From the time I pulled over until the time I was towed home, it
  seemed like the battery continued to drain; although the dome light
  came on and the clock was ticking when I stalled out, by the time I
  got home the clock was dead and the dome light was gone.>>

Here it does sound like the battery did die, but here again, check out the
alternator output with a fully charged battery. If the van sits for extended
periods, or is not run enough, the battery will discharge at a constant rate.
Should this be the case, you would need to park near a plug where you could
run an extension cord to a "smart" charger such as a BATTERY TENDER, which
will maintain a full charge on your battery and knock on and off as necessary.
I use them of several of my vehicles that are "run occasionally".

<<Everything looked OK: alternator belt was tight, connections solid,
alternator and battery are of fairly recent vintage, etc., etc.>>

Here again, check the alternator output, you could have a bad diode or other
problems.

<<The  only thing anomalous is that there was moisture on the sheetmetal in
front of the fuse box, below the dash.  We've been having *lots* of  rain the
last few days.>>

If moisture is the problem, you can coat all your connections with "dielectric
grease" and it will keep them all dry and secure and prevent the corrosion
that occurs from repeated moisture infiltration.

<< I grabbed my amp meter and tested the current flowing from the  negative
terminal to ground: 25 mA, even after I pulled all the  fuses! >>

From this it would appear that you have a dead short. You must locate it and
clear it.

<<I charged the battery for 3-4 hours, and the sun came out and the weather
turned warm.  After the charge-up, the current drain  fluctuated between 3 mA
and 7mA, keeping time with the clock.  This  is the normal state of affairs.>>

This would nullify the previous concern.

<<So I'm thinking (hoping) that rain water leaking in past the  windshield was
the cause of my problems, and that a few days of dry  weather will make things
all right.>>

If you are leaking water past your windshield, the probable cause is not the
gasket, but one of rust, and a hole, around the windshield and under the
gasket. I am rebuilding an '80 model Westfalia and when I pulled all the glass
and gaskets, I found a number of rusty places, which were all the way through
the metal and had to be welded up. Those around the bottom of the windshield
WERE leaking.

<<And yet.....and yet......I'm not sure I really believe this.  Anybody  have
any thoughts on the matter?>>

Those are my thoughts on the matter and I hope they help.

Victor...
' 70 K�fer
' 77 K�fer
' 80 Westfalia

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 Tom Young               young@sherlock.SIMS.Berkeley.EDU
 Lafayette, CA  94549    '81 Vanagon
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