Keep blowing fuse for tow running lights / lights work fine on other vehicles.
 

I have a 2006 Super Duty that keep blowing the trailer tow running lights. The problem is, they work fine. They are LED's and there is no problem on three other vehicles. Truck has a factory harness. The trailer is a brand new utility trailer with a 7 pin connector. (I wanted back up lights on the trailer).
Anyone have any Ideas what's wrong?