2008 Ford Edge | Stereo Wiring Diagram 2008 Ford Edge Stereo Wiring Information. Radio Battery Constant 12v+ Wire: White/Red Radio Accessory Switched 12v+ Wire: Blue The stereo wiring diagram listed above is provided “as is” without any kind of warranty. Use of the information above is at your own risk. Leave a Reply. 2008 Ford Edge Car Stereo Wiring Diagram - ModifiedLife Whether your an expert Ford mobile electronics installer, Ford performance fan, Ford after market fan or a novice Ford enthusiast with a 2008 Ford Edge, a Ford car stereo wiring diagram can save yourself a lot of time. Automotive wiring in Ford vehicles are becoming increasing more difficult to identify due to the installation of more advanced factory electronics.