The attached PDF shows what I ended up identifying at the connector.
IIRC the switch switches between Live and High/Low/Washer. Double check using your switch and a multimeter of course but I think thats right. :$
Basically you need to find the 4 pins where you get continuity from one to the other three on high low and washer then wire up the motor as in this link.
You will need a relay to allow the park function, it wont park from the switch.