It's probably a 1/2" or 9/16" wrench, but it could be several sizes smaller also. Get a little 4" or 6" crescent and that will take care of it. Don't over tighten the clamps when you put them back on. I just grab my little 1/4" socket drive set.
Undo the negative cable, it's safer than undoing the positive cable. If you are using the wrench on the positive cable and the other end of the wrench touches something metal, it will cause a short through the wrench and it won't be pretty.
Ford thinks people drive their vehicles every day so they designed lots little electronics in the system that draw little bit of power all of the time. Both my F250 and Escape have to either have a trickle charger on them or the battery cable disconnected if I'm gone traveling in the MH. So much for professional engineering.......
Bill
