I did install an aftermarket vacuum cruise control unit. It uses vacuum
for engaging the throttle, the rest is electrical. Works great!
Includes cabling to brake-switch, extra switch for clutch, three button
control unit for dash mounting and speed sensor (coil/magnet) to be
mounted on one of the axles (e.g. CV).
It should be possible rewire the control unit to your turnsignal "stalk".
I started with the standard speedsensor, but replaced it later on with a
home-made sensor on the speedometer. I think you can use your speedsensor,
should fit on the other speedometer, but you might need some electronics
to match the signals.

The unit I installed:
http://www.conrad-anderson.co.uk/cruisecontrols/cruisecontrolssystems-ZT50N.htm
Alternative (basically the same):
http://www.waeco.com/pages/products/auto/04_d.htm

Jaap,
'87 Caravelle diesel

> Hi All,
> Does anyone have any experience,
> installing Cruise Control into a non-cruise Van?
> What is the best way, Vacuum (stock) or  electrical?
> I have a parts bus with cruise.
> Is it possible to (easily) mix & match,
> so as to have the stock Vanagon
> turn signal switch, speed sensors, etc.
> with an electrical, after market  Cruise?
> I've heard Electrical is much better than  Vacuum?
> What Vanagon parts are needed?
> Speed sensor, (whole speed ohmmeter unit)? brake &  clutch switches,
> relays, fuses etc.
> What brands, models etc, for the aftermarket  unit?
> Any help, greatly appreciated !!!
> Thanks!
> John...