Wiper Motor Difficulties

[PNJSNAK]

I have a used Lucas Wiper Motor Assembly that I have in my Cobra. I have made the mecahanism park the wipers to the drivers side. I am using a wiper 3 pos Lucas switch I got from Finish line. When the engine is off I put the key to ACC the volt gauge says 12 volts and the wipers are in the park position with the switch in the park position. I can move the switch to the low speed pos (middle) the wipers move at low speed and then move the switch back to the park position and the wipers park. I can even go to the high speed pos and they work and then they park.
Once I turn the motor over and approx 14 volts are on the gauge the wipers stay in the park position. But, once I move the switch to the run low or high the wipers go to that speed but when you move the switch to the off or park position the wipers still move at the low speed and do not park. Even if I shut the motor off and move the key to the ACC position the wipers still move and do not park.
I shut the battery switch off and then put it back on with the key in the ACC position and the wipers go to the park position.
I am confused, what is going on and what can I do to make the wipers only see 12 volts.
Puzzled.
Jim