Wipers won’t stay on

I believe on a T&C Limited, you have a sensor that detects water on your windshield and changes the rate of delay the wiper blades complete a cycle. So a sprinkle they will wipe with longer delays in the cycle and less delays in the cycle when it is down pouring. My assumption is that the sensor went bad, so it believes it is not detection rain. I belief the first setting is for this variable delay, second setting is for a more sensitive setting in the delay, and the last setting is just full speed. I hope this helps.