I couldn't find an accurate wiring diagram for my stereo without paying a ridiculous fee, and no one here that had one was willing to share it with me
, so I made one myself for everyone to use.
The wiring colors are pretty similar to earlier Camaros, but things are moved around in the actual connector, and they swapped the polarity of the wire colors for the right dash tweeter for some reason. I checked 3 times, because it didn't make sense, but the wires are swapped in the connector vs diagrams that can be found for earlier Camaros. I've also included a table on which outputs need to go to which inputs on a Fix 82/86. Forgive the smudging, this scan is from the actual diagram I worked off of while physically building out all the wiring for my stereo.
A word about LLJ Customs: Based on advice given here I purchased a loopback harness from LLJ customs to make these connections without cutting into the factory wiring. Having trusted that LLJ did the job right, it took me many many hours across 2 weeks until I decided the problem might be the harness and not my equipment. After cutting open the harness and examining it, I discovered that the harness was built very incorrectly with some really obvious mistakes (mismatched wire colors -- grey to green instead of green to green & grey to grey) and
nothing worked the way it was supposed to when I hooked it up. Nothing. I'm still pissed about all the time I wasted dicking around with the FIX86 wondering why nothing was working correctly. I had to entirely cut the harness open to fix all the problems which made the all of their nice finish work useless. The harness was missing
any connections for the tweeters & subs entirely. I even paid LLJ extra for the tweeter connections. The tweeter wires he included were threaded completely incorrectly through the harness for loopback and not even hooked up to anything! WTF dude? I had rebuild it properly with the tweeter connections looped back and then make four completely new runs for subs (rear deck speakers) to loopback. The terminals I paid extra for him to attach were hollow junk that pulled off with the most minor strain.
LLJ is absolutely unresponsive to any kind of communications. He took many weeks to ship it (only shipping after I complained 5 weeks after ordering it that I wanted a tracking number), and then just ignored any of my emails when I complained about all the mistakes they made building the harness. It was a waste of a lot of time and money.
0/10 I do not recommend purchasing a harness from LLJ Customs. Just find the connectors or a cheaper harness from someone else because you are going to have to rebuild it yourself anyway if you buy it from LLJ. Not worth the expense.
The BOSE head unit sends a tremendous amount of bass energy to the speakers. I'd guess the speakers they built are not very responsive except in mid range frequencies, so they compensated for that by just pumping a lot more power into the high and low ranges. Normal speakers when hooked up to the BOSE amp sound like garbage because of this. More importantly, when you run the calibration for the Fix 86, it will detune the bass so much to create a flat signal that after the calibration it will sound like all the bass is missing. The highs sound ok when corrected, so I did not do anything special about that, but there was definitely a problem with the bass.
After spending a lot of time doing calibrations over and over again to find the problem, I took a look at the manual which gave me an idea. The Fix86 manual says you need to zero out your EQs for calibration, and while I imagine this works for most factory stereos, it sounds like trash on our cars. However, there is very simple fix. When calibrating the Fix86, set the bass EQ on your headunit to it's minimum level (-12, I think). Run the calibration, then reset the bass EQ to zero. The sound will be much, much better after calibration, even without a Twk 88 it sounded pretty good.
It's also important to realize that the BOSE headunit really, really splits up the frequencies in different areas of the car. You
will need to use all 8 factory outputs to the Fix86, ignoring the center (more on that later). If you skip any of the 8 speakers, the Fix86 will not calibrate correctly and errors out (incomplete spectrum). Even if you do manage to get it to pass calibration, it will still sound bad like part of the audio range is missing. There are so many traps and gotchas when using this unit, I think I understand why it has a bad reputation for our cars. I really doubt a lot of installers put in the work to figure out the problems and do what needs to be done to make it work correctly. Following the above instructions, it actually sounds really good.
The center channel, door chimes, and turn signal clicks remain a pain points. There are only two signal processors that I am aware of that can handle more than 8 inputs, both are made by Helix and cost an arm and a leg. Without that, the center channel remains factory. Though I did not do this, my suggestion would be to put a 2 ohm resistor in
series with the center to quiet it down without killing it entirely. Be sure to choose one that is rated for enough power handling, probably 20-25w is a safe choice. The major consequence of doing nothing is that you cannot properly time align the rest of the system because you can hear the audio coming from the center earlier than everything else. It's a miracle that the Fix86/Twk88 work so quickly that there is no perceptible delay as it is. The center speaker also sounds somewhat mushy in comparison to the Hertz & Kenwood speakers I chose for the front. You might think you can just turn the gain up on the rest of the speakers, but that quickly proves impossible as the 800hz chime you cannot make any quieter due to factory restriction will blow out your ear drums every time you open the door with the car running. Gains have to be kept very low in order to keep the factory chimes and dings at a manageable level. This means the center will almost always be audible in your system.
The included photos below show the diagram I made as well as an uncorrected audio spectrum measurement from the factory BOSE system into the Fix86. It's pretty apparent that the front speaker's bass (blue curves) get way more energy around 50hz than everything else. The highs are clipped so bad you can't even see the peak. The rear speakers are more reasonable, but all the low frequencies go to the deck speakers in blue, while the mids and highs go to the speakers in the rear seats.