The BMW 528i was manufactured with a single-DIN stereo that provides sound to four quadraphonic loudspeakers. The replacement may need a wiring adapter harness and stereo adapter harness, which makes the installation easier. The average backyard stereo installer can replace the stock stereo in about an hour.
Remove the 528i dash panel in front of the stereo by pulling it firmly until it disengages the pop rivets on the rear. Set the panel aside. Remove the retainer screws that hold the radio in by turning them counterclockwise. Some optional stereos have a hidden screw behind the volume knob; be sure to remove this as well. Slide the stereo out of the dash and disconnect it from the wiring harness and antenna cable by pulling the relative wiring adapter plugs.
Wire a new harness adapter to the new radio unit using the wiring diagram provided in the adapter kit. The wiring adapter takes the input power and speaker output and routes it through the BMW wiring harness to the stock components. Secure all connections with a liberal amount of electrical tape or use crimping wire connectors for a more professional look.
Connect the wiring adapter to the wiring harness of the BMW, then slide the stereo into the opening on the dash. The opening should not require an adapter plate for standard single-DIN radios, but some rare models may not fit properly without one. The stereo should fit snugly and will remain in place when the radio mount tabs are bent inward. These are small cut outs on the side of the radio mount harness that will secure the stereo against jolts when they are bent against the backside of the dash with a screwdriver. Replace the mount screws by turning them clockwise, but do not over-tighten them into plastic. Replace the dash panel by pressing it onto the dashboard until the pop rivets engage.
