IIRC, on later model years the ISV "hums" only when engine running.
Possibly ONLY due to a change somewhere else in the wiring harness??

IIRC, some 2.1 ISV's had 2 contacts, some had 3.

Good info Neil...I'll check to see how my early '89 is configured

Patrick Spragge

From:   Neil N <musomuso@gmail.com>
To:     "Pat Spragge/RFAN" <Pat.Spragge@rfan.com>
Cc:     vanagon <vanagon@gerry.vanagon.com>
Date:   10/01/2015 11:05 AM
Subject:        Re: Idle Stabilizer Valve part numbering question

In Bentley wiring diagrams for '86, to '90 and up,
a change in wire gauge aside, I see the same
wiring scheme from ICU to the ISV.
On my '88 (which tends to use an '87 wiring diagram),
the ISV "hums" with key to ign. on, engine off.
IIRC, on later model years the ISV "hums" only when engine running.
Possibly ONLY due to a change somewhere else in the wiring harness??

IIRC, some 2.1 ISV's had 2 contacts, some had 3.
AFAIK, the connector at harness only has (ore uses), 2.

For point of reference, van-cafe.com shows 035.133.455F but out of stock.
http://www.van-cafe.com/home/van/page_436_754/idle-control-valve-alternative.html

Neil.

On Thu, Oct 1, 2015 at 10:01 AM, Pat Spragge/RFAN <Pat.Spragge@rfan.com>
wrote:
All,

I'm looking for a known good, used Idle Stab Valve as mine isn't working.
In my searching, I see both the spec'd 025 906 457A and a 037 906
457C...does anyone know what the difference is btwn the 025 and the 037?
Are they interchangeable in an '89 Digifant system?  They 'look'
identical.

Thx
Patrick Spragge
1989 Westfalia w/2.1
Mountain View, CA

--
Neil n

Blog: Vanagons, Westfalia, general

1988 Westy Images

1981 Westfalia "Jaco" Images, technical

Vanagon-Bus VAG Gas Engine Swap Group