Jim__H

When I bought my '06 last spring it came with a BOSS aftermarket head unit that I don't care much for but the most obvious issue with it is that it does not go off when I turn the car off. I finally got around to buying a replacement and I dove into it today, The always on problem was obvious right away, someone had spliced a second wire off of the constant 12V wire (yellow) and ran it to the ACC input on the BOSS. Problem is I don't see any switched power sources anywhere. There is what looks like a factory harness with a big connector but none of those wires are 12V when the ignition or ACC is on. Can someone tell me where I might find one?

Jim__H

Here is a photo of what I have. There are 8 wires that look like speaker wires that have been clipped, 6 RCA connectors, and a 24-pin connector fed by a harness. The connector holds 8 speaker wires, a ground, two orange, white, yellow and red/white wires. There is also a gray wire coming out of the harness that has been clipped. The yellow is constant 12V and none of the other four wires are energized even in ACC mode. The yellow wire coming out of the connector is the one that has been spliced, going to the BAT+ and ACC terminals on the BOSS. How much of this is stock?

madsonp

First of all an interface is needed with a aftermarket stereo installation on these cars, the most commonly used one on this forum it the PAC RP5-GM11 the latest version of which looks like this.


If the stereo was installed correctly, some sort of interface should have been used, it may differ than the one shown above. If they didn't use an interface, and just spliced into the wiring, this can cause all sorts of issues. The interfaces have the wiring for switched and constant power as you can see here.

The first thing I suggest you do is determine if you have an interface, and determine the brand, then go to that companies web site and look at the installation instructions for wiring it up. If you don't have an interface you might have a whole other can of worms. If you're not sure, post a photo of what you have, and we could probably help you through it.

madsonp

Well the copper colored open-ended wire aren't stock and neither are the RCA cables, do you have a picture of what's wired to the other end of the big gray connector (if anything)

backlater

install a fuse buddy on the wiper-washer fuse at the bcm

Jim__H

Thanks madsonp, I'm slipping over all the worms on the garage floor already but I didn't think this would be easy. Here are a couple more photos both into and out of the 24-pin connector. There are two connectors that plug into the BOSS, one for the speakers and one for power, antenna/remote, etc.

If there is a PAC, would I see it in this area or could it be mounted somewhere else? I doubt it's there, I don't get any chimes at all in the car.

I am totally up for installing an interface and making things right, I just hope there is a way forward on that and that the original wiring has not been screwed up to the point where that is not feasible.

madsonp

Yep, no interface, what a mess. Looks to me with the copper speaker wires and the RCA cables, they may have also installed an aftermarket amp some place. I suggest tracing the copper speaker wires and the RCA cables and see where they go. My guess is that you'll need to remove the center console to do so. When everything is connected properly to an interface it has all the connections needed for an aftermarket system install. Here's some guidance from the "How To" sections of this forum to show you have to remove the console, you'll need to do this anyway to properly install a new system. Let us know what you find when you follow the wires and RCA cables back to where they're hooked up to. Don't give up yet, there's still hope we can save it.
https://www.corvetteforum.com/how-to...igation-368176

Jim__H

Ok thanks, looks like my work is cut out for me. Well it won't be the first time I had to undo and fix a kluge from a previous owner. I'll keep you posted.
Jim

FatChance

In your picture, the red wire coming out of the grey connector should be 12v switched power. The yellow wire should be the12v constant power

Jim__H

The red wire is not energized in either ACC or with the engine running. I don't know why, yet.

I pulled the center console today, wasn't too bad but some of those connectors put up quite a struggle. After getting it out and gaining more access, I saw that all those extra wires are routed to the left side of the car and run underneath the door. If I had taken a hard look before tearing into it I would have seen that, sigh.

As for the interface...looking at the PAC unit I am now not so sure I it is worth the effort in my case. Here is a list of what it is supposed to do:

• Retains OnStar® and functions when the factory radio is replaced
• Retains steering wheel controls (pre-programmed)
• Retains factory Bluetooth (2009+ model vehicles)
• Retains rear seat audio controls
• Retains all warning chimes (chime module included)
• Retains back-up sensors/park assist
• Retains factory BOSE and premium Bose audio systems (Does not retain fade in digital systems)
• Compatible with non-amplified audio systems
• Chime volume adjustment (factory buttons)
• Rear Seat Entertainment Retention
• Retained accessory power output (RAP)
• Reverse Wire output
• VSS (Vehicle Speed Sense) output
• Illumination output, Parking brake output
• Includes antenna adapter

I don't even know what some of this stuff is, several items are irrelevant, and others I don't need or won't miss. Is there some reason, other than the items on this list, for going to the effort to install the interface? I am thinking of wiring the new radio in without it.

madsonp

Well it just depends on the head unit you get, and the features you have on your car that you want to retain or not. PAC makes other interfaces that don't retain as many things that'll work just fine also. https://catalog.pac-audio.com/?fc=mo...m=1881&submit= If you see one that better suits your needs I suggest shopping around for it, as you can usually find it cheaper than what PAC sells them for. Either way I highly recommend installing an interface so the new head unit communicates with the cars canbus system properly. If you do get an interface, and your new head unit doesn't support all the connections on it, you just simply tape off those connections, and don't hook them up to anything. Do you know what connections from those you listed that you don't need and which ones you do ? Here's a short description of what everyone of these features is for.
OnStar retention - If you subscribe to OnStar you'll want this feature.
Steering wheel controls - If you car has this feature, you'll want this. If your car doesn't have these I can give you some guidance on how to add them if you're interested.
Bluetooth retention - chances are if you get a new head unit that has Bluetooth built into it, you won't need this.
Rear seat audio (RSE) and audio controls - of course the Vette's don't need this as we have no rear seats.
Warning chimes - These are good to have a retain to have the car chimes to warn you of certain things i.e. if you leave your head lights on.
Backup sensors - Not needed on the Vette.
Retains Bose - This is something you'll wand it running the stock amplifier, even if it not "Bose" because all Corvettes have a stock amplifier
Retained accessory power (RAP)- with this, the power to the head unit remains on when you shut the car off, until a door is opened or 10 minutes passes, then it shuts it off automatically. Good to have if you're waiting in the car for the wife to come out of the store.
Reverse wire output - needed if you install a backup camera (which I highly recommend), This activates the head unit to display the camera automatically anytime the car is put in reverse. I personally also installed a front camera on my car which is handy to help avoid damage to the front end when pulling up to parking blocks.
Vehicle speed sensor (VSS) - Needed if you get a aftermarket Navigation head unit which makes it more accurate, also used on some non navigations specific units to make smart phone navigation more accurate vis CarPlay etc.
Illumination output - This is needed to dim the display of the head unit automatically whenever the head lights are turn on, some of the head units with screens can be bright, so it's a good feature to retain.
Parking Brake output - This is needed to make some changes on some head units, so you don't try to make them while driving potentially distracting you, it unlocks these features when the car is stopped, and the parking brake applied. There're was to bypass thiis however if you choose to.

I'm personally running the GM1A-RST in mine, with my Pioneer navigation system, and I also have steering wheel controls. The OnStar retention wasn't needed in my case because OnStar is no longer supported on my car, so to disable this feature on the interface, I just pulled the OnStar fues in the fuse panel. So I hope this help you make a decision, let me know if you have any other questions.

Jim__H

Lots of useful info there, some of those features I need and some I don't. Thanks I will explore what the other units offer.

Looks like one of the POs installed a big sound system in the car, pulled it before selling it but left all the cables.

madsonp

Yep, that's what I figured, hopefully they didn't butcher things up to bad, at least the car side of the gray connector shown in your pictures looks intact, that's a good thing. I'd suggest checking all the connectors on the stock amp to make sure everything looks good there, and that they're connected up and have nothing spliced into them. It's located under the front of the passenger side carpet, next to the fuse panel on the left side, I used to have a good photo of it to show you but I can't find it, perhaps someone else reading this thread has a picture of it they could share. Let me know what you find.

Jim__H

I'm still in the discovery phase, at the end of yesterday's session I took a quick look for the amplifier and didn't see it but I did not try too hard, but yes a key part for sure. That is an impressive set of cables that someone ran though, including a massive one about the gauge of a jumper cable and it goes from the battery area all the way to the back of the car. Might be enough copper in there to fund the interface, haha.

madsonp

My guess is the cable from the battery is the power cable for the aftermarket amp that used to be there, if it's connected to the positive terminal of the battery, make sure the end of it is taped off, or just disconnect it from the battery so it doesn't short out. Might be worth leaving in place should you decide to add a subwoofer or something.

madsonp

Ok, I found a picture of the stock amp in the C6, it's one I found on the internet so disregard all the other stuff on it. The amp is shown with the red arrow. Again this is to the left of the fuse box under the passenger side carpet.

Jim__H

Thanks! I got to mine yesterday, here is a photo, looks like the connections are unmolested. I looked on the PAC site and I think I'll go with the bare bones model, GM1A-R, if I can find one. It is pretty much all that I need and it looks like the installation is easier. I also yanked all those miles of cables out of the car, I am sure I won't be needing them.

So when I get the interface I guess I have some wiring to sort out. The only wiring schematic I have is in my Haynes manual and it is not really helping much.The ones I have found on the forum are not readable, is there a good source that you know of?

madsonp

Well that's a good sign. The only wiring you should have to do then is wire up the interface to the new head units wiring, then it should just plug right into the gray connector in your previous photos, and if everything else is good, it should fire right up. Here's the wire instructions for the GM1A-R https://catalog.pac-audio.com/index....ttachment=1900 And here's a place that looks like they have it in stock https://www.soundoftristate.com/pac-gm1a-r As far as wiring diagrams for your car, if you get a hold of @papawana he'll send you the complete wiring diagrams for your 06 for free. https://www.corvetteforum.com/forums...ams-offer.html

Jim__H

Ok, great and thanks. If you are saying that the PAC interface replaces the connector that plugs into that harness connector that is good to hear. I took a quick look at that connector yesterday and noticed that there is no connection between the red wire coming from the harness and the red ACC wire that was supposed to go to the BOSS. I did not trace that red harness wire back to the fuse to verify but if so then that explains why the previous guy spliced off the BAT+ wire. Not sure why he couldn't figure that out though, considering all the other wiring he had to do.

Jim

madsonp

So yes, you unplug the mess that's there now (see pic) then the interface will plug right into it.



So this connector will plug into the factory connector in place of the one shown above.