Almost everything the ECM does is by controlling or measuring something to
the chassis. In the control world this is known as sinking logic, as
compared to sourcing logic where that work is done on the positive side. For
example the injectors get feed battery voltage and the ECU completes the
circuit to the chassis to open them. The temp sensors complete the circuit
to ground from the ECU. Follow the wiring diagram and stick with it.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Dick Wong
Sent: Monday, October 21, 2013 1:56 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Wiring color question

I noticed that there are brown/white wires going into the ECM.  So those are
only grounded when the ECM is "on" or ECM programming switches it to ground?
What if I connected the brown/white wire directly to a ground lug on the
chassis?

Thanks.

On Mon, Oct 21, 2013 at 10:45 AM, Neil N <musomuso@gmail.com> wrote:

> brown/white is for switched grounds?   (i.e. for dome light)
>
> If the gauge is the same, if one is used in place of the other, maybe
> the only issue is slight confusion for someone else trouble shooting
> that wiring?
>
>
>
> On Sun, Oct 20, 2013 at 11:59 PM, Dick Wong
<sailingfc@dslextreme.com>wrote:
>
>>
>> What is the functional difference between the Brown ground wire and
>> the Brown/White wire?  What if I use the Brown/White circuit instead
>> of just Brown (direct ground)?
>>
>>
>
> --
> Neil n
>
> Blog: tubaneil.blogspot.ca
>
> '88 Westy http://tinyurl.com/c8rlw6p
>
> '81 VanaJetta 2.0 "Jaco"  http://tubaneil.googlepages.com/
>
> Vanagon VAG *Gas* inline-VR Engine Swap Group:
>
> http://tinyurl.com/d7gd5ej
>