General Ducato camper wipers wont go off

[r10crw]

Hi guys Im having a problem with my 96 ducato van. Two weeks ago the wipers decided to come on permantly and I was advised to replace the stalk at a cost of 100 pounds only to find out there still on permantly. Is there a control unit for determining speed control that has maybe fried? Or is this done within the motor itself. Any help greatly appreciated. Thanks Craig.