I have to assume the ICU is using the 'start' signal for something. I
could only speculate as to what. I have heard from someone who knows
that the module is a little more complicated than it might seem.

Vanagon Digifant is not alone in using an ICU as a separate module to
control the idle air valve. Other European brands of similar vintage use
one as well. BMW 3 Series comes to mind and we replaced the ICU on one a
few times over the years that we owned it. Not a cheap part back then.
At least in the BMW is was mounted in a very protected spot along with
the ECU. I think mid/late 1980s Audis and Mercedes did likewise. No, I
don't think the ICUs from those vehicles are interchangeable with
Vanagons. Here is a link to some for sale.

http://www.ebay.com/sch/i.html?_odkw=bmw+icu&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.Xbmw+e30+idle+module&_nkw=bmw+e30+idle+module&_sacat=0

Mark

Neil N wrote:
> Right, ok. Thanks Mark. Thinking now, the only possible scenario I can
> see mattering is if one were testing a newly designed IS module on an
> automatic transmission Vanagon. Otherwise I see what you mean. That
> switch you refer to is moot.
>
> So in terms of the IS module itself, while the starter is engaged, is
> 50 + sent momentarily to the IS module to disable the IS module while
> engine is firing up?    ( to ensure the ISV stays in the correct
> position?)
>
> Neil.
>
> On 11/14/13, mark drillock <mdrillock@cox.net> wrote:
>
>> The clue is the /50. It means it is the starter signal 50. Why they felt
>> the need to mention the Auto Trans Selector is a mystery other than in
>> auto trans models the starter signal 50 comes through the trans selector
>> switch to keep you from starting the engine while in gear.
>>
>> Mark
>
>
>