1999 - 2000 ford winstar sel power locks very

On the 2000 Windstar that I was working on, the casing for the door lock actuators had split and the lock knob on the top of the door would twitch when I hit the button, but would not lock or unlock fully. I replaced the door lock actuators (in stock at my local dealership) and cleared up the problem. Also check the bushings that link the rods inside the doors. They are plastic and occasionally wear out

you need to replace the door lock acuators