Stereo Wire Harness Ford Focus 00 01 02 03 04 2000 2001 2002 2003 2004 (car radio wiring installation parts) Wire Harness for Ford Focous 2000 - 2004 WIRE HARNESS: Wire Harness. When replacing your factory radio with an after-market car stereo, a wire harness is a must for a quick installation. It eliminates cutting your OE radio plug helping to maintain your cars value. After connecting it, your install is simple as the wires will color-match and easily connect to the after-market stereo. Without a wiring harness, you must cut the factory harness and then test each wire to connect to your radio. NOTE: Locate your vehicle in the application guide. Cross-reference your vehicle's make and model to determine which installation parts are required to complete your car stereo installation. The installation parts consist of a Dash Kit, Wire Harness and in some cases an Antenna Adapter is also required.