Vacuum source for transfer case switch - 94 Jimmy

Can anyone tell me where to find the vacuum source for the transfer case switch (which powers the vacuum actuator [servo]) on a 1994 Jimmy - 4.3L 4wd automatic?
I have a schematic, but it doesn't show where on the intake the source is.
What should the vacuum measure at the actuator?
Thanks in advance, steve
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Feeds from the same port as the HVAC controls. Passenger side near the distributor, if it's a CPI motor (black upper plenum). Dunno how much vacuum is supposed to be there.
On 16 Dec 2003 06:44:53 -0800, snipped-for-privacy@pwi.net (Steve) wrote:

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line comes off the back of the intake plenum and goes over to the drivers side to a check valve, from there it splits to the hvac, vacum ball, and the 4wd... should read close to engine vacum at the switch.... Bobo

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Thanks, Bobo... do you know of any photos or illustrations of the check valve and the intake plenum?
From the check valve / splitter combination, there was one hose about 2" long that was just hanging out unattached to anything else... is this a relief tube or should it be connected to something?
thanks again steve

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On 17 Dec 2003 09:10:52 -0800, snipped-for-privacy@pwi.net (Steve) wrote:

I'm trying REALLY hard to recall what mine looked like, I replaced these lines this past spring. I don't recall how many hooked up there, I know one was HVAC, one was the t-case switch. There MAY have been one for the cruise on there as well. Maybe the 3rd was the vacuum ball, as Bobo says, or there were 4 off that manifold of sorts.
It's raining right now and I really don't feel line taking a walk out to the truck to pop the hood and look. Maybe once this storm passes I can take a digital pic and put it up somewhere, if someone else hasn't found one...

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