So I attempted to follow the "How To" guide (link at bottom for convenience) for splicing an AUX input into the CD player of my head unit and everything just kind of went **** up. After getting my bottom cover off, which used a completely different number of screws than the tutorial, I was greeted by this random PCB board. After taking off the heat sink and some extra screws on the sides, I managed to get it off and... well, I found this. It doesn't look anything like I expected, so I ended up having to read the board underneath to confirm (I think) the location of the L and R channel wires. I had to assume the wire between them was the ground, but who knows. The power wire was a crap shoot. I followed the tutorial and spliced into the 7th wire from the "front", where the L channel wire was, hoping it was the same.
Once I got the head unit installed though, it just didn't work right. If I leave the switch On, it plays the CD as normal. However, when I switch it off, I don't get the Err message, the CD music stops, and the CD player acts like its trying to track. It says its on the same track, but you can hear it moving around like its trying to find something. After a while, it spits the CD out and goes to the radio. Any time I plug my phone into the AUX, I get nothing... and my phone just plays through it's own speaker. This happens whether or not the power is switched On or Off, the "nothing" from my phone will silence the music from the CD.
To be clear, I have NO IDEA what I'm doing. My knowledge of small electronics is limited at best and I'm just coasting off of intuition mostly. I feel like the AUX is wired correctly because of how it interrupts the CD audio, but I'm wondering if I've spliced into the wrong wire for power to the CD player? I feel like, when switched Off, it shouldn't try and track... it shouldn't do anything, right? I did notice, as you can see in one pic, that towards the bottom wires 11 and 12 seem to be labeled S10V and S5V respectively. Are one of these the power to the CD player?
I feel like I'm smoking crack... I don't know how anything works anymore. I swear, if I walked outside and it started raining cupcakes, I wouldn't even question it at this point.
Please, can anyone help me out and explain what I have messed up? I've included pics that I think are relevant, but if you need anything else just let me know. Once we get this figured out and running, I figured I'd put together an addendum to that How To post and document the changes.
Thank you!

*** NOTE: Pics were taken after I had drug it back out of the Firebird and cracked it open for the second time, that's why there's wires and splices in it already.

https://ls1tech.com/how-tos/a/camaro...adapter-417993

CONCLUSION: None of them work. None of the wires on the CD ribbon will cut power to the player as in the tutorial. If you have a similar setup, this tutorial will not work and needs to be changed to reflect that.

 

Here is a link to the original Jason Novak modification thread detailing installation of an auxiliary jack in a CD head unit. It's rather old (it references Radio Shack part numbers) but then the head units are old as well so it's still relevant. It's been a long time since I read through it, but I'll bet it will give you some insight into your problem:

Add an aux input without adapter

 

Thank you, WhiteBird. I couldn't find much in the thread itself, it looks like this was before they stared doing the switch to cut CD power, but I did reach out to Jason. Thank you for the reference!

 

Yeah it's been a long time since I've really looked at this. L and R were found on pins 1 and 3 opposite the colored wire, though I think differed in some cases. It's definitely the right connector, labeled CD, and I can't quite see the pins you connected to, I assume 1 and 3. I don't recall ever tapping into power myself and switching that,I don't recall the purpose, something to save wear and tear on the motor? If you undo that part does it work, or at least get rid of the errors? Seems like is the cause. It's possible your audio is on other pins, maybe double-check the post to see other possibilities, otherwise I found the audio using a set of old headphones cutting off the end and putting one wire to ground, and probing each of the pins on the connector while it was playing until I heard audio

 

Thank you, Jason. Yes, I've got L and R audio on pins 1 and 3 respectively and the ground wired to 2. I might just ground to the case to remove that variable, but I'll poke around with a multimeter and check the resistance from the pin to the exposed contact that has the labels just to make sure.
I'm not sure why they're cutting power myself, unless maybe its to prevent noise from the CD? I noticed there were some people getting some noise bleed in the original thread... maybe that's it.
But even when that circuit was closed with the switch, I still couldn't get playback from my phone, it acted like there wasn't even an AUX plugged in but all the connections were tight. But then again, if my channel splices are wrong...
I'll poke around tonight and report back. I'd love to check with headphones, but I don't have a way to power the unit on. Powering it in the car would be a tight fit, I don't have much slack in my harness.

 

So I double checked my AUX connections and they all seem right. I got resistance from the labeled contact to the appropriate pin, and even from the contact and pin to the AUX port itself. I couldn't make out much from checking the power connections, seems like 11-14 all show resistance through the main power (pin #10 on the black connector in back), so I didn't learn much there.
However, after hooking up my phone and a set of headphones to the male/female AUX cord that I'm using for a wiring harness, I also got no playback there... soooo it might just be a bad cord? Its brand new, but the smallest I could find was 6 feet, so its twisted and coiled up a good bit. I'm hoping that ends up being the issue, although I still don't understand why I'm not getting the typical Err message that I should be getting when the CD power is switched off. As far as I'm aware, a bad cord shouldn't be any different than not having anything plugged in to a working one :/
Anyway, I'll try and snag a new cord and see if that's the issue. I'm not convinced that my power switch is located correctly at pin 7, but if the tutorial was right about the left, right, and ground pins, then odds are it was right about pin 7. I can feel my brain getting smoother with each passing year... I'll update once I have a working M/F AUX setup.

 

Yes, the factory that it's showing "ERR" makes it sound like a data or power line was cut that shouldn't be. I doubt it can even detect if the analog audio lines are cut and doesn't really know what's going on with them. When I was testing I had an extra harness and connected to a 12v power supply and some speakers. It does seem weird though to kill power to the player, since as I recall the mod works by the car playing a CD but you're replacing it's output and they likely need to communicate to allow this

 

Just food for thought, I think I found the thread that originated the "7 pin switch" method. I'm sure it's OP could speak far better on it that I can, but he mentions having to trick the firmware into leaving the channel open for the CD that the AUX is piggy backing off of. I'm guessing as opposed to switching back to the radio?
Oddly enough though, the radio he's working on isn't even a Monsoon. As someone there mentions, its doubtful GM would have terribly different architecture between their head units, but still. I'd really like to know how he discovered that pin 7 was the wire to cut and apply the same methodology to mine.

https://ls1tech.com/forums/wiring-st...st-method.html

 

It's great to see Jason helping out here! Frankly, I agree with him that the cutting of power to the CD may be the issue. Even the auxiliary adapters which used the external CD changer port often required that the optional changer still be present in order for the head unit to provide audio signal to the port. I would recommend trying the auxiliary connection by itself (without the power switch) first to determine if you can get your phone working with it before moving on to adding power control. With electronics (and programming, etc.) it's better to start with the small steps and add modifications later because it then becomes obvious what change caused a problem if one occurs after a subsequent modification.

It is not advisable for you to connect the audio signal negative to a chassis ground - the system uses a "floating" ground rather than a "common" ground, so connecting the negative signal to chassis ground could damage the system.

 

Same here, I appreciate his help on the matter!
WhiteBird, thank you for your input on the ground wire. Luckily though the wire I spliced into for ground checked out when I checked the resistances yesterday, so I didn't feel the need to relocate it.
So I picked up another (tested and working) M/F cable today, and everything fed through the console. Head unit is back together and everything is ready to go. I'll hook everything back up tomorrow and see how it goes and report back. Its a shame if I end up not needing the power switch though, I have already modified and repurposed a 2010-2015 Camaro side mirror switch to use as an AUX/Switch combo. I even airbrushed the switch gray to match the other buttons and got waterslides to relabel the AUX and CD side, haha.

 

New cord installed, and while its still doing the same thing I mentioned in my first post, I DO hear the noise from taking the AUX cord in and out, so there is some communication there.
Alright, so I've learned a couple things. There seems to be 2 methods to install an AUX port: one from the posted tutorial that uses a 3 pin AUX and a switch to cut CD power, and Jason's method that uses a 5 pin AUX alone. Since I opted for the posted tutorial, I used a 3 pin AUX and my switch doesn't work because pin 7 doesn't control the CD player power on my head unit. I found someone else who had the same problem, and a future post of his alludes to him having found the correct pin, but he doesn't mention which one. I've sent him a message to pick his brain.
https://ls1tech.com/forums/wiring-st...l#post20427350
If I don't hear from him, I'll just have to add a switch for every pin and try all of them to see which is the correct one. If that fails, I'll order a 5 pin USB and do Jason's method, I'm confident that'll work. I'm really keen to do the switch method though since I've already bought/modified the parts, and now I have a gaping hole in my TCS switch cover that's fit to the switch I've made. I'd rather not have a switch that does nothing, but if push comes to shove... :/

UPDATE: I wired switches to pins 10-14, no luck. I initially had success with wire 11 (the one labeled S10V), but my phone audio would only play for about 10 seconds before it would kick back to the radio and give me E20 and E22 codes. Going to try the other 5 wires as I get time, soldering these tiny wires are a pain and take forever.

 

Conclusion, none of them work.
Whitebird, can you have that tutorial amended to exclude "all" Firebird head units? It is not applicable as written to all models and may save another poor soul from hacking up his wires in the future. Maybe it should be rewritten altogether to conform to Jason's method instead of this method that uses a 3 pin AUX and a switch.
Thank you guys for your help!

 

Huh, so I wired in a 5 pin AUX as in Jason's method, but now my CD audio is extremely quiet when the AUX isn't plugged in... Like it almost just sounds like background noise at normal volume. From what I've read, I should be able to retain CD functionality, does anyone know where I might have went wrong?
I did wire the AUX ground to the CD ground on the second wire instead of the case, would that be the cause?