Alright this is just as serious as can be, so instead of KFC... I've always had a bar of Lava in an orange bag hanging by the spigot; this works like a charm.
An FYI, my '98 twin Taurus fans will not activate high speed unless both inputs are powered. That is to say that each hot lead to the fan must be energized in order for the high speed to be reached.
A bench test, with jumpers, should be performed if you are in doubt then adjust your wiring...