Windstar 2000 SEL door lock problem

While driving sometimes I hear lock/unlock noises. It occurs totally randomly. Ca anyone share what might be the problem?

thanks
Arifaa

Do the door lock knobs go up or down when this happens? The doors on my 2000 lock automatically when put into gear. Is your remote button getting accidentally activated? Could also be a defective switch.

No i dont see them going up and down it just gives the sound/noise of going up and down. My also lock automatically when I put it in gear.