Just for reference, the heated element is the aerial. The banding round the edge that you can see is on all versions.
on the pre Jan 1990 models it was visible, Ford just moved it when the face lifted the car in 1990.
if you go to the amp box under the shelf trim, the wires go straight from that to the window element connections. I would check the small feed wire to the amplifier as that is what powers the aerial part up. It is normally red/white and is also in the back of the radio. If this is good, most likely the amplifier box is dead. Even if some of the heated elements are not working on the window, there is still a circuit for the aerial.