2004 Ford Focus | Stereo Wiring Diagram 2004 Ford Focus Stereo Wiring Information. Radio Battery Constant 12v+ Wire: Yellow/Green. Radio Accessory Switched 12v+ Wire: Orange/Black. Radio Ground Wire: Black/Green. Radio Illumination Wire: Orange/Black. Left Front Speaker Positive Wire (+): White/Black. Left Front Speaker Negative Wire Chevorlet · Stereo Wiring Diagram · Ford · Request Stereo Diagrams 2004 Ford Focus Car Audio Wiring Guide - ModifiedLife Whether your an expert Ford Focus mobile electronics installer, Ford Focus fanatic, or a novice Ford Focus enthusiast with a 2004 Ford Focus, a car stereo wiring diagram can save yourself a lot of time. Automotive wiring in a 2004 Ford Focus vehicles are becoming increasing more difficult to identify due to the installation..