I recently picked up a 2007 SType with 21,000 miles on it. I think the 4.2 will be powerful enough to pull a small trailer of 3500 lbs with electric brakes. My goal is to tour many of our national parks in comfort and elegance beginning next year. Does anyone have a wiring diagram for a 7 pin harness? I understand installing a separate ground wire is recommended, but a little expertise would be appreciated. I was surprised to see trailer hitches are still available. Any info would be appreciated.