I have the same one on my AT '87 Westy.  Is yours newly installed, or
has this always been a problem since installation?  Mine did this upon
new installation (by me) and had me puzzled for a while.  I added a
later model Golf/ Jetta vacuum reservoir along with all the lines and
vacuum check tee line, trimming everything to length for the Vanagon
engine bay.  I placed the reservoir in the left space in front of the
taillight area, retained by the original bungee strap.  This solved the
issue and I've never had that problem since.  As someone already stated,
it could be a vacuum leak also.

Mike B.

On 11/3/2012 10:33 PM, Edward Maglott wrote:
> hello, I have one of the usual aftermarket Audiovox cruise controls
> on my 86 with AT.  I think it's model CCS-100?  I use the magnet
> speed sensor kit on my drive shaft.  It's not working well.  It
> engages briefly and then immediately disengages.  It will then
> attempt to resume to that speed if I press that button, but
> immediately disengage.  That makes me think that it is at least
> remembering the speed I set it to.  I've gone through the
> troubleshooting of all the wires as the instruction manual specifies,
> and everything is good.  I'm wondering if I could devise some way to
> monitor it from the driver's seat to figure out what is going
> on.  Thanks for any advice.
>
> Edward