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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?
Comments: To: neil N <musomuso@GMAIL.COM>
In-Reply-To:  <c4e7c5f90808091159i7ef434d5oe44eaec33bac498@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

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/ > > >


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