2006 BMW 3-Series OE Wiring Harnesses & Stereo Adapters BMW 3-Series 2006, 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. 2006 BMW 330i Car Radio Harness Wire Color Chart Whether your an expert BMW 330i mobile electronics installer, BMW 330i fanatic, or a novice BMW 330i enthusiast with a 2006 BMW 330i, a car stereo wiring diagram can save yourself a lot of time. Automotive wiring in a 2006 BMW 330i vehicles are becoming increasing more difficult to identify due to the installation of more advanced factory oem electronics.