Electricel connectors

I replaced the engine in a 99 Taraus and I have one connector on the drivers side fire wall side of the engine I can not find were to connect it to. It's black and female. There is another one just like it on the passanger side that plugs into a connecoter located on the speed sincer. I believe this should also be plugged into the tranny and I belive it has something to do with shifting and speed sincing.