Hey matt,
I had exhausted all avenues of 2 speed wiper conversions because as usual my set up was different...
so i was once again flying solo.
what made my 2 speed conversion problematic was the fact of having wiper switch on the indicator stalk ala VB-VK commodore.
A negative ground switch will not work with a preslite (XM) motor.
The easy option would be to use a EH or similar switch but I did not want a wiper switchon the dashboard.
The VN motor allowed me to use a negative groud switch (activating relays) to provide the (+) for fast and slow speeds.
FWIW Ken was a great help in supplying me an XM motor and other info however he also told me the VB-VK switch would not (or would be difficult) to work... I did have to do my own research here to prove it to myself.
from that research I did find the VN comm wiper motor to be easier to wire up.
other options for 2 speed wipers are the Castle Auto electric kits for around $300.
my conversion cost me the $20 for the motor, and $29 for a brand new switch.
the biggest indignity is performing a conversion and having things that do not function properly or reducing the useability of the car.. since the intended purpose of any modification is to improve the car.. right?!
for those needing a wireing diagram, there is a guy who did all the work and posted it here... the principles of operation are the same for a Preslite and Lucas motor.
http://www.spriteclub.com/tech%5Cwipers.htmall my R&D here for you to enjoy!
Cheers
Ed