I just bought and 89 firebird with the 2.8 v6. The owner before me installed a very poor quality tape deck. i just pulled out everything that e did. i found the 4 sets of speaker wires but i don;t know what the other 8 wires are. could someone please help. please email me with any responces. If you have a wiring diagram i would be very appreciative. Thanks.

 

Go to the junkyard; find another GM car with an unmolested radio harness. Cut it out of the junk car, and keep it as long as you can.

Go back to your car, trim all the wires to an even length and strip them. Using solder and good quality 3M electrical tape, connect the new harness to your car...the wire colors should all match right up. Tightly wrap the entire harness in black tape for a factory look. Now your car is as good as new.

Next, go to a car audio shop and buy an adaptor plug. It will plug right into the plug on your car, and it will contain wire colors that match up to most aftermarket radios.

There's one other thing to note. I'm pretty sure that by 1989, the Firebirds were using the new-style (smaller) GM radio plug. If you want your car perfect, make sure you get the correct plug. But if you don't care about perfection, it doesn't matter, because you can buy the proper adapter either way.