So I have almost no car audio knowledge but some basic electronics knowledge(and I mean basic). Heres what I know, this 1993 Z28 has the head unit you see in the picture, two door speakers that frankly suck, nothing in the back seat panel speakers, and the Bose sub box in the back with a big burn mark on the circuit board connected to the sub.

I took pics of the wiring in the panels and I have looked at wiring diagrams and it seems that some of the colors match up but some dont. That or Im just an idiot who doesnt know how to read. Heres what I found when I googled 1993 camaro radio wiring chart.

"Car Radio Battery Constant 12v+ Wire: Orange
Car Radio Accessory Switched 12v+ Wire: Yellow
Car Radio Ground Wire: Black
Car Radio Illumination Wire: Gray
Car Stereo Dimmer Wire: Brown
Car Stereo Antenna Trigger Wire: Pink
Car Stereo Amp Trigger Wire: N/A
Car Stereo Amplifier Location: N/A
Car Audio Front Speakers Size: 6 1/2″ Speakers
Car Audio Front Speakers Location: Doors
Left Front Speaker Positive Wire (+): Tan
Left Front Speaker Negative Wire (-): Gray
Right Front Speaker Positive Wire (+): Light Green
Right Front Speaker Negative Wire (-): Dark Green
Car Audio Rear Speakers Size: 6 1/2″ Speakers
Car Audio Rear Speakers Location: Side Panels
Left Rear Speaker Positive Wire (+): Yellow
Left Rear Speaker Negative Wire (-): Brown
Right Rear Speaker Positive Wire (+): Dark Blue
Right Rear Speaker Negative Wire (-): Light Blue"

Now some of these colors match up and I have pics below. Some of these I see and some I dont. The yellow and brown it shows on the left rear are there but theres 2 yellow wires in that bundle back there. Can anyone help me understand which wire is which? Heres a few pics of what Ive found pulling out the panels. Please forgive me atrocious finger nails. I promptly clipped them after taking these pics. lol

This is the head unit.



Here is the front driver side door speaker. Looks pretty old and I hear it kind of cut in and out a little bit. Theres one on the passenger side as well that works ok.



I popped out the speaker shield thing and.. no speakers on both sides! So only the front 2 speakers "work"(and i say that loosely because they dont work very good) and theres nothing in the back 2 speaker slots.



Ok so driver side rear seat panel, this is the color of the wires.



Heres another, looks like someone stripped a section of the brown and two yellow wires.



Here we find another wire running through the driver side rear panel. This wire has electrical tape wrapped around it.



Here is what was in the taped wire.



This is what I found in the trunk on the driver side plugging in to the sub box and one shielded set of wires.



H

Heres the circuit board(amp?) to the subwoofer. Nice burn spot. Do you think this is basically toast?



Heres the colors of the wires going into the adapter for the sub box.



And another look just for good measure.



This is what was in the trunk on the driver side.



And another look at the colors of the wires.



Ok now that we've followed the wires on the driver side back to the trunk.. here is what I see on the passenger side rear door panel. Looks like its JUST the antenna wire.



Following the antenna wire back to the trunk, I found that someone must have put a new antenna on it and never connected it. Two male ends and no way to connect them up properly without an adapter.



I checked out amazon and found a female to female adapter for GM vehicles that looks like it should work and was only 6 bucks so I put in an order for one. Hopefully it works.
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Anyways, Ive done some googling and it seems like the only way to be able to replace the head unit is with an adapter but Im not really sure what to look for. If I want to replace the front speakers and add in rear speakers.. do I have to redo the wiring or can I use the wiring already in there? Why am I not seeing like.. the blue wires it says in the wiring diagram? Is it just easier for me to replace the wiring entirely if I get a new head unit? I really dont mind taking the interior apart to do the wiring if necessary.

I havent purchased anything yet but I can see alot of confusion from people who have tried to do this and I just need some help because I have never done anything like this before and it feels like its a little bit over my head.

 

Ok I just unbolted the head unit and took a look at the wires in the back.

more 93 camaro radio pics - Album on Imgur
^^
Heres a link to the pics in an album on imgur.

Now I know for sure some of these wires dont match up. That wiring diagram says theres a dark blue and a light blue and I only see one blue at all.

 

have you seen this yet http://shbox.com/1/bose_wiring.jpg yep the three speaker system is weird.

 

i rewired all the speakers on mine.