There is a rain sensor that sounds like it has gone out or the BCM might be having issues. lets start by unplugging the sensor. here is the location and the wiper wiring diagrams below so you can see how the system works. Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.