I have a 07 F150 with the 5.4, my battery always has a corotion build up on it even if i clean it. does anyone have any ideas or if there is a draw on the battery does anyone know where it is?

 

More than likely the alternator voltage is too high and the battery is being consistently overcharged resulting in a high rate of disassociation of the electolyte with outgassing.
Lead/acid batteries outgas on charge and discharge so electrolyte loss is built into the system. Some high profile batteries have electrolyte reassociation recovery features that compensate for the loss, but those batteries cost a fortune.

Check your system voltage. Ideally it should be 13.9 volts, but more than likely it's up around 16 or 17. If the voltage is too high, the alternator reg is screwing up.

Clean up the corrosion with a heavy concentration of baking soda in water; make a paste and apply it to the area to neutralise the acid or get an aerosol can of acid-detector-neutraliser.