2001 Ford Ranger Wiper control problem

My wipers will only run in normal or fast speed - no intermittent - and won't stop and park when the wiper switch is turned off. I replaced the switch and still have the same problem and must turn off the engine with the wipers in the right position and the wiper switch turned off to get them to park and turn off. I tried moving the relays around (there are three identical ones under the hood) with the same results. The washer function has the same problem - the wipers continue to run unless I turn the engine off.