The size of car radios, also known as head-units, are classified into two categories: DIN and Double DIN. DIN radios are 2 inches tall by 7 inches wide, whereas Double DIN radios are 4 inches tall by 7 inches wide. The vehicle in which the Double DIN radio is being installed must have a Double DIN size port in the dash. Fortunately, many BMWs do have stock Double DIN openings.
Disconnect the car's battery. This will prevent a short.
Remove the old radio. Locate the edges of the dash trim panel. This is the small space where the dash ends around the radio. Insert a flat-head screwdriver into that space and pry off the dash. Do this slowly and carefully. Pry off the dash every few inches until it pops off. Use the same screwdriver to unscrew the existing radio from the vehicle.
Unhook any wires from the back of the radio. The wires will be attached to clips that hook into the back of the existing radio. Simply unclip them. Remove the antenna wire from the back of the radio.
Install the E36 radio. Because the E36 is a stock radio, meaning it was designed for use in the BMW, there will be no need for a wire harness or hard wiring. The new radio should clip right into the vehicle's connector clips. There should be two main clips, of differing sizes, which will make it easier for the installer. Plug the antenna into the labeled antenna port.
Insert the radio back into the vehicle and screw it into the dash. Reconnect the power to the vehicle. Turn on the car and test the radio.
