There's a four-pin outlet on my Alaskan which might be a good configuration: pos & neg 12V, and running lights. The whole arrangement works pretty well as I remember from my grandfather's Alaskan & '66 Ford Camper Special, and they're obtainable at etrailer.com. I can post a pic this weekend when I go to WY to work on my IH. I gave the pigtail to my buddy who owns the shop there because I'm going to hardwire the camper to the truck & won't need it.