wiper motor wont "park"?? 74 duster

My last wiper motor on my 74 duster decided it only wanted to work on high mach 3 speed. It never parked either. Anyway, bought a new wiper motor and it doesnt park either. Its a 3 speed motor. I think I got the first motor and switch from a 74 dart swinger/valiant junk/parts car. Or a different 74 duster. There is a brown wire coming from the firewall connector-wiper motor bulk connector-engine bay side that has a female spade connector end. I have no idea where that goes. Trying to find a wiring diagram for 74 duster on here still. What can be the reasons for wipers not "parking"? The brown wire that isnt connected is on the 3rd firewall bulk connector-closest to driver side fender and is at the top and on the right. Hope this all helps. Thanks in advance.