2003 Ford Focus Stereo Wiring Information
Radio Constant 12V+ Wire: Orange/Black (Thick Wire)
Radio Switched 12V+ Wire: Yellow/Green
Radio Ground Wire: Black/Yellow and Black/Green
Radio Illumination Wire: Orange/Black (Thin Wire)
Radio Amp Trigger Wire: None
Left Front Speaker Wire (+): White/Black
Left Front Speaker Wire (-): Gray/Black
Right Front Speaker Wire (+): White/Red
Right Front Speaker Wire (-): Gray/Red
Left Rear Speaker Wire (+): White/Purple
Left Rear Speaker Wire (-): Gray/White
Right Rear Speaker Wire (+): White
Right Rear Speaker Wire (-): Gray
The following information is currently not available:
Radio Dimmer Wire
Radio Antenna Trigger Wire
Front Speakers Size
Rear Speakers Size
*If you know any of the above or any other missing information please use the comment box below to notify us.
Had to install a cruise control on my 12 Focus, (Rostra brand aftermarket), and had to find a 12v ignition wire. on YouTube there is an install guide for it Rostra 250-9612 and they found it. Left side of the drivers foot well is a wiring harness going vertically by the foot well light. inside of that harness is a Brown wire with yellow stripe that is your ignition wire. Strip off the insulation carefully and only as much as you need! I do not know what gauge it is, sorry. I stripped off about a 1/2 inch section and wrapped my accessory wire around it and taped, unfortunately no soldering equip.Worked great and don’t see why it couldn’t be used for trigger wire. Without know how much juice normally runs through can not recommend using for powering a stereo, but for low amp applications it should work and does for my cruise switch.