2004 Mazda MPV Car Stereo Wiring Guide - ModifiedLife Whether your an expert Mazda MPV mobile electronics installer, Mazda MPV fanatic, or a novice Mazda MPV enthusiast with a 2004 Mazda MPV, a car stereo wiring diagram can save yourself a lot of time. Automotive wiring in a 2004 Mazda MPV vehicles are becoming increasing more difficult to identify due to the installation of more advanced factory oem electronics. 2004 Mazda MPV OE Wiring Harnesses & Stereo Adapters Mazda MPV 2004, Factory Replacement Wiring Harness by Metra®, with OEM Radio Plug. For factory stereo. This high-quality Metra wiring harness is just what you need to replace your defective or aged factory wiring harness.