Look on the driverside right behind the radio there will be a black looking box with two relays attached to it. It is the black one you can feel it chiming if you touch it. It has a couple slits in it on the front. Hope this helps.
also, on my 88 GT, i found the connector for it under the steering column. unplugged it and all was good. doing what Jeff said is probably easier though.
Here is the ford part number on it VE6AB-10D840-A1A . It is a 3 inch by 3 inch by 1 inch looking box thing. it and the 2 relays are held on by two screws at the far right under the dash kinda next to the hood release.