Step 1: Tools
Radio/Cassette Removal Tools
Soldering Iron w/ solder
3.5 mm jack
3.5 mm male to male cord
10K Ohm resistor (brown black orange) x 2
Dremel or drill
Remove radio/cassette player using manufacturer's tools.
Remove top cover by removing the two screws, then prying gently with a bladed screw driver.
Disconnect the magnetic head from the circuit board and cut off the ribbon wire.
Solder on five new wires to the connector. If you look on the other side of the connectors, it will show the inputs as Common, Front Left, Front Right, Rear Right, and Rear Left.
Solder the Right inputs together and the left inputs together.
Solder a 10K ohm resister (brown, black, orange) between the connector and the 3.5 mm jack. Add tape to prevent shorts.
Solder the other end to a 3.5 mm jack (Sleeve=Common, Ring=Right, Tip=Left).
Plug 3.5 mm male to male cord into the 3.5 mm jack.
Carefully pry the faceplate off.
Using a Dremel or a drill, create a small hole in the cassette door for the cord.
Put everything back together and replace radio/cassette player to the vehicle’s dash.
Turn the volume on low for both the device and the radio/cassette to test for audio.