wipers go haywire on chrysler town & country

That fact that the wiper motor runs at all, even at the wrong times, proves it is okay. It's the Body Computer that tells the motor when to run and has been very well known for causing your problem. Loss of any delay functions, loss of all functions, failure to stop running, and turning on unexpectedly are the most common problems caused by the ridiculously complicated computer. Before assuming the computer is the problem, you might want to try a new multifunction switch just to be safe. They were known to cause "phantom wipe" which was the wipers turning on by themselves, taking one swipe across the windshield, then turning off. The switch does not turn on and off like they did for decades when the common sense wipers worked just fine without a computer. Instead, the insane engineers designed the switch to send varying voltages to the computer corresponding to the various settings, then the computer interprets those voltages and activates that function. Sometimes the voltage sent by the switch is borderline between the "off" and first "delay" settings. The computer can get confused and turn on at the wrong time.