tell me ..
All Knowledgeable One,

why is the blue wire D + tied into the Oxygen Sensor elasped milage counter
box and light ..
and why does it say 'cat elapsed milage counter' at the box, track 46,
page   97.107  ?

I need a blow-by-blow too.

----- Original Message -----
From: "David Beierl" <dbeierl@ATTGLOBAL.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, March 26, 2011 2:08 PM
Subject: Re: Alternator question

> At 12:44 PM 3/26/2011, Greg Potts wrote:
>>As Dennis suspected, the battery light does not come on when I first
>>turn the key before starting the van. Also possibly related: about a
>>week ago I also lost all my dash illumination. The gauges and coolant
>>warning light still function however; only the battery indicator and
>>dash lights seem to be affected.
>
> The only common point is the fact that both wires go through the
> panel connector.
>
>
>>I have removed and inspected the cluster and everything looks OK; I
>>tried swapping the LED's between the OXS and the battery but no luck.
>
> The LED itself actually carries only a minor part of the "tickler"
> current that starts the alternator going.  The rest is carried by a
> resistor in parallel - it's the large one you can see labeled as R3
> on 90.8 fig. 4.  When ALT lights were incandescents that drew a
> couple hundred milliamps this wasn't necessary.  But in this case the
> LED will carry around 15-20 ma, and the 150 ohm resistor about 80 or so.
>
>
>>I also checked the connection of the blue wire on the back of the
>>alternator and it appears to be clean and well seated.
>
> Pull that wire from the D+ terminal and check the key-on
> voltage.  Should be +12 but by the symptoms it will likely be
> zero.  If it's zero, follow it back to the panel and find out where
> it goes to +12.
>
> If by chance it *is* +12, stick your milliammeter on it and see how
> much current it will deliver to ground.  *Ought* to be in the range
> of 100 ma (and the light should light), but again I'm not expecting
> that it will be.  Ground it or connect it back to the alternator and
> again follow it back to see where it turns to +12.*  Can you read the
> wiring diagram (97.104 et. seq., tracks 6 and 51) or do you need a
> blow-by-blow?
>
> *if it goes to +12 as soon as you hook it back to D+ that indicates
> an alternator problem, but that seems unlikely since you've swapped
> alternators.
>
> Yrs,
> d