Some day all the manufactures will conform to The Society of Automotive Engineers tow standard, SAE J2807 standard, which they all agreed to comply in 2009 by 2013.
I think at this point Toyota is the only manufacture that have met the standard. Ford is saying by 2015 it will be there on their trucks.
http://rvingwithmarkpolk.com/2012/12...7-update-2013/