Waveski, can you post a pic of your wiper motor? It must be different than mine. The dash control isn't a "valve" but just a lever to actuate the slide switch on the wiper motor through a short pushrod.
Here's a couple pics. The first is of the dash control from the FAM, and the second is showing the operating lever and the slide valve on the top of the motor. I added a couple arrows showing the movementn of the operating lever and the slide switch.
If you just used a valve to cut off the vacuum supply to the motor, the wipers would stop in any position instead of going to a park position.
I'll move this thread over to Interiors. There's another post there with more info on vacuum motors.
HERE
