We'll there appears to be some differences in the two models ... Does anyone have the setup listings for Energi
The owner's manual has a section about recreational towing. It tells you exactly what to do to set up whatever you own for towing. If you don't have one handy you can search for and download a PDF version easily. Ford support is a good place to go
Ford Support.
BTW, based on the info in a previous C-Max towing thread, I did install a charge line. Not tested since I have yet to tow the car any great distance.