Date:         Sun, 24 Feb 2008 06:16:28 -0800
Reply-To:     Mark Drillock <mdrillock@COX.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Mark Drillock <mdrillock@COX.NET>
Subject:      Re: Bentley wiring diagram. Questions on how to read.
Comments: cc: neil N <musomuso@GMAIL.COM>
In-Reply-To:  <c4e7c5f90802231550u5300fc93yfe40137fe752b795@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Neil, it sounds like you are getting the hang of the Bentley wiring
scheme now. In any case, there is no good reason to use an extra relay
panel from the Jetta just to get a provision for the fuel pump relay.
That fuel pump relay is performing such a simple function that can be
performed easily by a standard relay in the engine compartment. The
relay is controlled by ECU pin 6 providing a pseudo ground for the relay
coil. The power side of the coil is +12 jumpered over from the high
power input side of the relay contacts.

Whenever the key is on, +12 is provided to both the relay coil and the
relay contact input. But the ECU only provides "ground" for the relay
coil whenever IT thinks the fuel pump should run. Be sure to maintain
this safety feature of only running the FP when the ECU says to.

The fuel pump relay output also provides +12 power for the heater inside
the OX sensor via the OX heater control module J208.


Mark


neil N wrote:
> Hi all.
>
> P 97.57 Vanagon Bentley. Emergency Flasher Relay. A 20 gauge wire
> stops with reference to track #78. I go to #78 on following page. It
> stops at the track. I can only assume it goes to ground.
>
> And for those with a '93-'99 Jetta Bentley......
>
> Diagram 97-18, the fuel pump motor shows one connection to 31 (ground
> or battery negative) and the other to track #42, then via a 28 pin
> connector to #41. Both appear to go to ground. Two ground wires to the
> motor?
>
> If a wire on a diagram stops, shows a track number reference in a box,
> but the track number has nothing going from it, does that simply mean
> the wire in question goes to ground? If that's the case, then the
> Jetta fuel pump has two ground connections?? Where's + ?
>
> Hope this makes sense. I'm puzzled!
>
>
> --
> Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
>
> http://web.mac.com/tubaneil
> http://tubaneil.googlepages.com/
>