Just for starters, the ZX4 is a four-door sedan, while the ZX3 body is the three-door hatchback. At the very least, that will mean differences in the wiring loom as regards door-courtesy and boot/tailgate lights. Cars will have different wiring looms depending on their transmission, too, so even if the engine is the same in both cars, the loom might not be.Then there's the more basic question of whether they're actually the same model of Ford Focus. Ford Australia switched to the all-new second-gen Focus in April 2005, and if your 2005 Focus is that newer version, the wiring will not be compatible with the 2001 model. But even if they're from the same generation of Focus, swapping a wiring loom from one car to another involves many, many hours of work.