I wanted to test the cruise control pump for my customer's 90 GL and I
didn't realise that the really nice troubleshooting chart in my Bentley
actually allows you to do that with the until still installed in the van
(who would have thought the Bentley would have a well thought out, step
by step, troubleshooting diagram for something as esoteric is cruise
control when they don't have it for something as life threatening as the
coolant system?).  So I took the bugger out (two phillips head screws)
and tested it on the bench.  There are three connectors on the pump and
they are basically
Ground,
Power to solenoid valve
Power to pump

You can play around with it until you get the right combo.  It didn't
seem to hurt anything when the vacuum pump went in reverse and was
putting out air instead of sucking it in:-)  The cool thing I figured
out is this:
The pump will pump when electricity is supplied to it.  However it will
not hold a vacuum unless the solenoid valve is also energised as well.
Then if you shut off the pump but leave the solenoid valve energised it
will hold vacuum until you shut the valve off as well.  Kind of cool for
just a little gaget.  Also the pumps from other vehicles are the same as
the Vanagon.  I had one that I compared my customer's pump too.  It was
from an Audi GT Coupe 87.  It has a different mounting bracket but the
pump was exactly the same and I imagine that a Jetta or Golf of a
similar vintage with cruise would also have the same pump.  If anyone
needs a good, tested, used one, let me know.  I have one on the shelf
now :-)

Hope you are enjoying the lovely weather we are having today.

Thanks,
Ken Wilford
John 3:16
http://www.vanagain.com
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