For the trailer lighting, my '96 is pretty normal.
Newer windstars (1999 and newer) may have a Rear Electronics Module (REM) and there have been posts (do a search) on trailer lighting not being a direct hook up......a adaptor box being needed.
Perhaps someone with experience with trailer lighting on newer windstars will chime in.
When I installed my transmission cooler.....I installed it on the front of the evaporator coils above the front bumper.....
This was to reduce stone hits.
I used the hoses on the driver's side.....between the transmission and the bottom of the radiator assembly.
I have the fluid flow out of the transmission.....into the radiator cooler......then through the auxillary cooler....and back into the transmission.
I would recommend that you check for low speed radiator fan operation.....with the engine at idle......in Park......select a A/C setting.......to have the A/C ON.
Then check to see that the radiator fans come on.....and STAY on.
If they do not stay on......you may have a broken low speed fan dropping resistor for the radiator fans.
This resistor is mounted on top of the front, inner bumper.......
You can see the resistor by looking down behind the passenger side headlight....
Here is a link to a picture of it on my '96
http://rides.webshots.com/photo/2458...11220610ybouky
In stop and go traffic in hot weather.....I keep my A/C ON....which keeps the radiator fans running at low speed when the vehicle is stopped or moving slowly.....which keeps the transmission MUCH cooler.....as well as keeping the engine cooler.