This is a WAG but is it b/c the ICU is only using hall input as a
measure of a running engine and no more? And-or the ICU will react and
control the idle stab. valve faster using switches than it would using
engine RPM drop as a reference? Interesting question though.

Mark: Thanks. The guts of the ICU look fairly involved (though I
appreciate that the electronics are somewhat old school given that
IC's aside, you can actually see all the caps, resistors etc.)

image

http://images.thesamba.com/vw/gallery/pix/1111642.jpg

Neil.

On 11/14/13, Brett Ne <brettn777@gmail.com> wrote:

> Okay, now it's time for a dumb question: why do we need input signals from
> the power steering pump and air conditioner?

--
Neil n

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