The power to the switch does not come from the relay, it goes to the relay from the switch, and is supplied elsewhere.
Put up the terminal numbers as that may give a better clue, or check part number with ford.
I know the power to the front switch disappeared on my sapphy so I just wired across from rear, as engine always running when screens are on anyway, front's only powered up under running whereas rear is whenever ignition is on pos 2.
tabetha