2012 Hyundai Elantra | Stereo Wiring Diagram 2012 Hyundai Elantra. April 28th, 2013 Posted in Hyundai Elantra. 2012 Hyundai Elantra Stereo Wiring Information. Radio Battery Constant 12V+ Wire: 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. 2012 Hyundai Elantra Car Stereo Wiring Instructions Whether your an expert Hyundai Elantra mobile electronics installer, Hyundai Elantra fanatic, or a novice Hyundai Elantra enthusiast with a 2012 Hyundai Elantra, a car stereo wiring diagram can save yourself a lot of time. Automotive wiring in a 2012 Hyundai Elantra vehicles are becoming increasing more difficult to identify due to the installation of more advanced factory oem electronics.