OEM 7 pin trailer harness HELP!

[ChuckD]

The smaller one is the power steering cooler.

 

[Eric]

Correct, never seen a power steering oil cooler before. What is nice is that Ford still utilizes the trans cooler built into the radiator as well so essentailly you have the trans fluid traveling through the radiator as well as the external cooler, should be fine for most towing duties.