Check the continuity on all of the fusible links. They were the culprit on
my old chevy when it decided to quit, I do not remember how many, but a
couple of them were above the distributor on the firewall. They are easy to
find due to the obvious weak spot in the insulation.
----- Original Message -----
From: "Don Hanson" <dhanson@GORGE.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, June 25, 2008 2:16 PM
Subject: electrical testing proceedure question..Not van specific, but..

> ...It may  help some listee who's maybe wanting to learn to test the
> output
> of a van's alternator.
>
>  I'm trying to figure why my SO's old chev farm truck won't keep starting.
> 70s era 350 Chev that's been un-killable. She uses it carelessly around
> the
> place to drag, haul horse sh*t, go to the dump, etc.  It gets absolutely
> no
> care..Lately,  she's been jumping it to make it run..today, I get the
> pleasant task of 'fixing it'..Love the Honey-do's...not..but..
>
>  So, the battery is 7 years old..Probably time for a new one, yes?  After
> cleaning all the ground points and the terminals and putting it on the
> charger overnight, it shows 12.57 at the terminals when the truck is
> running
> and the same when it is not running...
>  "Aha!" I think, "The alternator is shot, too"  So I dismantle enough so I
> can put my multimeter onto the alternator terminals, but I realize I know
> not what to expect or haven't a clue as to how to diagnose the readings I
> get.  There are two smaller wires leading to a double spade plug in a
> rubber
> boot. I get a low voltage reading across those like about .4 or somesuch..
> There is one larger wire on a ring connector that is bolted on to a post
> on
> the alternator.  That one disappears under the headers, perhaps going to
> the
> starter?..anyway, I read the same voltage, truck running,  (12.57) off the
> large post (output?) as I get off the battery terminals when I read
> directly
> across the battery..I assume, and this is the question, that the large
> wire
> is the output for the alternator and should read +13~ v..right?  My van, I
> get a reading across the battery of around 13.4 when the motor is
> on...12.7
> or so when it's not running.
> Did I do right?  Should I get more than "ambient-- same as the battery"
> voltage from that larger terminal on the alternator?  Should I pull the
> alternator and take it to my local autoparts, where they  advertise "Free
> Electrical testing"?  And get another battery at the same time?  Help...I
> am
> an electrical dunce..
>  Thanks and sorry the question isn't Van-centric on a Wednesday, yet.
>
>  Don Hanson