Hello, welcome and thanks for asking your question. My name is*****'m a Certified Auto Technician with 28+ years experience. I will do my best to assist you. please keep in mind that I may need to ask questions of you before I can answer. When you reply please feel free to add as much detailed information as possible pertaining to your concern.
There are a few possibilities for this concern. It could be caused by a faulty Park Switch in the Wiper Motor assembly, it could be a wiring issue with the wiper park circuit or it could be an internal problem with the BCM (Body Control Module).
There are a couple ways that it can be diagnosed. The best way would begin by scanning the BCM. This module can only be accessed by a capable scanner. A "Generic" OBDII scanner doesn't have the capability to communicate with the BCM. You may also be able to diagnose it if you have a Multi Meter and a 12 Volt Test Light to check a few things.
If you have access to these tools and basic hand tools and want to fix this yourself, let me know, I'll gather some wiring diagrams and connector pin charts and for a small fee can step you through a procedure to get this figured out..
Let me know if interested, either way, I can post wiring diagrams for you here if needed. Let me know and I'll be happy to gather this info for you. I'll need the last 8 digits of the VIN so I can gather the correct wiring diagrams for you...
Keep me posted...