Date: Sat, 9 Aug 2008 12:39:37 -0700
Reply-To: mdrillock <mdrillock@COX.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: mdrillock <mdrillock@COX.NET>
Subject: Re: Bentley wiring typo?
In-Reply-To: <c4e7c5f90808091159i7ef434d5oe44eaec33bac498@mail.gmail.com>
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My Bentley does not have that page but the wiring diagram sounds right.
It may be a confusing oddity but VW often 'grounds' the fridge relay
coil with the wiring connection to the starter motor coil. The voltage
from the alternator blue wire triggers the fridge relay on whenever that
voltage finds a path to ground on the other leg of the relay coil. This
means that during normal operation a small amount of current is always
flowing through the starter coil from the fridge relay coil. Not enough
to actuate the starter by a long shot but a possible issue for some as I
mention below.
This is not a true ground but it is an effective one. It also adds
another level of certainty to turning off the fridge relay during
starting. During starting this pseudo ground becomes a positive voltage
and disables the fridge relay regardless of the charging status of the
alternator.
They did not do this on the fridge relay of all Westy models and there
is no strong reason for you to do it this way now. They used this same
method with factory aux battery relays and it makes better sense for
that one.
(This use of the starter coil as a pseudo ground causes a big problem if
someone tries to add a 'hard start relay'. The added starting relay can
be triggered on by the voltage passing through the fridge relay and this
will engage the starter motor while the engine is already running. The
solution for this is to unplug the wire from the fridge relay that goes
to the starter circuit and add a simple ground wire between that relay
leg and the relay mounting screw)
Mark
neil N wrote:
> Hi all.
>
> I'm sorting out my hand brake "turns off" engine issue. Dennis Haynes
> kindly wrote and indicated a lack of a fridge relay might the problem.
> I'll connect the fridge relay from my 182A downstream from the blue
> wire to aux battery relay to see if it helps.
>
> I'm using the '81 camper wiring diagram, but in checking "camper"
> wiring, I'm curious about 97.32e of Bentley.
>
> It shows "to ignition/starter switch terminal 50" from 85 and "To
> alternator terminal D+" from 86.
>
> Does the ground for the relay coil come from the case of the relay?
>
> I only have a 182A fridge relay in hand. (plastic case)
>
> Just curious.
>
> Thanks,
>
> Neil.
>
>
>
> --
> Neil Nicholson '81 JettaWesty "Jaco
> http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines
> http://web.mac.com/tubaneil
> http://tubaneil.googlepages.com/
>
>
>