I have a F-150 Supercrew that the center post on electrical plug on the trailor light adapter does not work, ican't find any blown fuses or broken wires,
I looked at 2 other F-150's and they don't work either????

 

In youre trailer tow kit you should have recieved a wiring pig tail conector (brake controler) and two relays one large for battery charge to rear plug and one small relay for back up lights. If you look at the power distrabution box under the hood on the drivers side tou will see a place for four relays in a row right after the fuses, one of the holes should be open this is wher you install the relay. if you dont have one get one from the dealer. That should make youre plug work, everything else is hooked up.