another wiper problem????

i have a 94 grand prix and at first my wife tells me the wipers stopped working,upon raising the hood i noticed they were caught on the lip of the hood ,upon freeing them they worked again with the exception that upon turning them off did not turn them off completly,they would after turning the switch completly off would jerk back and forth at short distances quickly,not completly shut off,if you turn the switch on they would act normal,short, long and at different intervals as they are time delay wipers, but turning them off started they jumping back and forth from there wiper rest under the hood,pulling the fuse will of course stop them,putting the fuse back in and turning the key to acc. or start will start them in action again. thanks