Does anyone know what this plug is for?

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axekick

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My deck seems to be working but it’s not getting sound to the speakers so I removed it to see if I could find the problem. I didn’t really see anything wrong but there was this plug behind it that wasn’t connected to anything. Any idea what it’s for?
 

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Tonyv__

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Edit. Before you read below, did you just install this radio or has it been in there and the speakers stopped? If you’re just installing now then read below.



No but I’m willing to bet your problem is the factory amp needing to have power. A lot of people get stuck here, myself included.

quick googling tells me that the factory amp remote wire is orange. It will be orange on the factory side of harness, not the aftermarket plug and play harness. Find that orange wire and connect it to the “remote” wire on your new head unit. That will provide 12v to the amp to power it on for the speakers.
 
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axekick

axekick

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I bought this truck with lots of problems that I'm working through one at a time. The deck was in it but I never heard it make sound. The PO made a mess of some things. There are wires for an aftermarket sub amp, but I still suspect you might be right. I thought about ordering a new interface harness with instructions and just redoing it cleanly, but they're kind of expensive. I need to do some diagnosis to make sure that'll even work.

Could that plug have anything to do with Onstar?
 

Tonyv__

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I bought this truck with lots of problems that I'm working through one at a time. The deck was in it but I never heard it make sound. The PO made a mess of some things. There are wires for an aftermarket sub amp, but I still suspect you might be right. I thought about ordering a new interface harness with instructions and just redoing it cleanly, but they're kind of expensive. I need to do some diagnosis to make sure that'll even work.

Could that plug have anything to do with Onstar?
Cleaning up other people’s mess is the worst. It’s very possible that they had an amp for the speakers and just took it out. One thing you could look for is to see how many sets of RCA wires were ran to the aftermarket amp area. If just one set, then I would think they probably only had a bass amp. But if two sets of rcas or more than they definitely had an amp for the speakers, and when they took it out, you lost all audio to the speakers.

The wire harness that you have is definitely the cheaper version but it definitely works as long as nothing else has been messed with from the previous owner. I’ve used them many times. I almost never buy the expensive interfaces on GM trucks. I just know with them cheap harnesses. You have to run your own remote for the radio and you have to run a remote for the factory amp if yours is equipped with that.

But of course you don’t know what the previous owner did to just sell you that truck
 

TollKeeper

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I would start by installing a factory deck, and make sure the system in its entirety is working as OEM intended. Also since it has speaker wires, I would go around to every door, and shine a light thru the speaker grill to ensure that there is even a speaker in there. If there are speakers in there, are they factory? Then they are likely wired to the OEM wiring. Are they aftermarket? Then it could be a toss up on how they are wired, factory or to some other location.

I am assuming you have a BOSE headunit from the factory, you can get one, turn the truck on to assessory, and then plug in the OEM deck, and it will work until you cycle the key.

This will get you to a starting point of knowing what needs to be done. If everything works, then you can get the OEM deck unlocked, and put your dash back together, or you can continue down the aftermarket route, and get it working.

OEM decks can usually be had really cheap from a salvage yard. You would just need to verify that you have a BOSE truck, or a none-BOSE truck, and get a radio that reflects that.

You might even get lucky and see if one of our members has a Tech2 that lives in your area. I have one, but I do not live in Texas.

I know we have a thread around here that tells where everyone lives that has a Tech2.

Edit: That additional plug is not for On-Star. Likely for steering wheel controls, or XM unit.
 
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axekick

axekick

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Ah. Good advice. I think I will go that route. It’s definitely a Bose system but I think the amp may not be hooked up. The door panel I’ve taken off so far had an original speaker in it in good condition. So far, the messes the po made are mostly a bunch of pretty well run relay wires for lights and amp and stuff, but I haven’t seen any harness hacks. Some things are just left unplugged for no reason that I can tell, like the power mirror on the drivers side. I just plugged it in and it works. I would have no problem just running a factory Bose deck with some kind of Bluetooth input. I had one in an 06 table that I built on here years ago and it sounded good enough for me. I’ll check the junkyard or get a buddy to grab me one while he’s there. I’ll update when I get it fixed.
 

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