2004 Cadillac Escalade OE Wiring Harnesses & Stereo Cadillac Escalade 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. 2004 Cadillac Escalade Car Radio Wiring Diagram Whether your an expert Cadillac mobile electronics installer or a novice Cadillac enthusiast with a 2004 Cadillac Escalade, a Cadillac car stereo wiring diagram can save yourself a lot of time. Automotive wiring in Cadillac vehicles are becoming increasing more difficult to identify due to the installation of more advanced factory electronics.