You might have problems with the wiring diagrams on the Haynes manual... they just copied it right out of their Mondeo manual.
I tried to trace a short I had, Haynes was no use. None of the wire colors were the same in the engine fuse box. I had to return it and go buy a Chilton manual (which didn't help either... diagrams were too simple).
Anyway, if you look at the diagrams, you'll see things like heated windshields, dim-dip headlights, heated seats, etc.
