To access the components of the shifter linkage, you'll need to work from underneath the vehicle, removing some components of the transmission tunnel's interior trim to reach the linkage. There might be some adjustment rods or connecting components that could be considered part of the "cable" system, but it's not a simple cable like you might find in a manual transmission car.
If you're experiencing shifting problems, it's best to take your Windstar to a mechanic. Diagnosing and repairing shift linkage issues requires specific knowledge and the right tools. Attempting to work on it without this expertise could cause more damage.