I'd have to look at a wiring diagram for what terminals are what. the FSM is available as a down load here on mud
the 12 volt positive should be switched power, not hot all the time, just when key is on
when wiper switch is turned off, it grounds the park function until it is parked, if not...
1 positive power
1 park ground
1 low speed ground
1 high speed ground
are the wipers working at all?
does it have a stock steering column? is the switch still in it?
any of the stock wires below the wiper motor?
stock system uses ground, thru the switch, to control the functions