Date:         Fri, 23 Jul 2010 00:23:08 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: A/C Wiring/electrical help (pic)
Comments: To: Robert Fisher <garciasghostvw@gmail.com>
In-Reply-To:  <AANLkTilBh-6rDc9ZytLeSbjkzasQpSCMDcPr0Wm7wYcc@mail.gmail.c om>
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At 12:02 AM 7/23/2010 Friday, Robert Fisher wrote:
>Well that'll get me started... I was thinking I'd pull and test each
>relay first.

Makes sense.  Also good to make sure that anything that ought to be
grounded actually is -- grounds are easy to find on the schematic,
much easier than actually understanding it.  It may also be an easy
preliminary to squirt some contact cleaner inside any control
switches and give them some exercise.  After that, though, you're
down to understanding from the schematic what controls the operation,
then following through on the vehicle to find out where it goes pear-shaped.

>I guess I should've made it more clear that part of the link (I
>think there were two strips) did indeed melt through; that pic is
>from after I put it back together somewhat.

Ok -- it *was* rather surprising to see the link (as I thought)
undamaged.  This type of problem is the major cause of false blowing
of fuses, since they respond to heat no matter where it comes from.

Final note for tonight -- when looking for high-resistance
connections (not actual open circuits), what counts as "high
resistance" is so low that common multimeters can't measure it; and
meters that can do it cost a lot more than you want to pay.  So what
we do instead is essentially fake a very sensitive ohmmeter by
passing a current through the circuit and measuring voltage drops
(which is precisely what an ohmmeter does).  Our little digital
meters will measure millivolts very handily.  In fact we don't bother
to figure out the ohms at that point, since what we're trying to do
is have as much voltage drop as possible be across the load, and as
little as possible across the wiring and connections to and from
it.  In your case no doubt all the voltage drop in some relevant
circuit will be across some connection or relay or stretch of wire,
and that will be the problem.

>Thanks!

Your're welcome.

d