Thread: Stereo wiring revisited..

These should be what you need:

Not sure what year this is for (maybe a 97?). What stereo are you trying to install? Stock, aftermarket?? Need some info here. If it's an aftermarket deck then you can likely get a harness adapter for it without worrying what wire is which and cutting the stock harness up. I installed a new Alpine in my 00 GT with a plug and play adapter and also retained my steering wheel controls with another adapter.

Originally Posted by FordMan77

Not sure what year this is for (maybe a 97?). What stereo are you trying to install? Stock, aftermarket?? Need some info here. If it's an aftermarket deck then you can likely get a harness adapter for it without worrying what wire is which and cutting the stock harness up. I installed a new Alpine in my 00 GT with a plug and play adapter and also retained my steering wheel controls with another adapter.

Sorry... 97' GTP, Stereo is an off-brand aftermarket. I just got this car used and it had no stereo in it, but the harness to the head unit is there. Here's the wiring schematic for the stereo;

Originally Posted by Mad Bohemian

Thanks Wstefan20, that looks like exactly what I needed!
I'm thinking I will have to get a steering wheel interface kit to use my stock steering wheel controls?

Yup. Though I agree with Scotty, it's much easier just to get the harness. Good luck!

Well, it's
Car - 1
Me - 0 .. in triple overtime :P
Actually I got everything installed and working (didn't do the steering wheel controls at this time) Back up camera, GPS everything works fine.... except for the passenger side front speaker. So I did some trouble shooting. Verified that the speaker is fine and I have output from the unit to through the wiring harness with an ohm meter. Both wires in the door have no continuity to the wiring harness, so I started stripping the passenger side of the dash down. Took off the glovebox door and the kick panel 'shelf' that goes to the firewall, that's when I noticed this plug handing down:


You can see another plug to the right nearby, but they do not reach each other and the are not compatible..
This is the plug on the right


this is plug on the left


This is where it gets crazy....The plug on the right has the same dark green and bright green wires that the wire harness has, so just for grins I did a continuity check from the wire harness at the stereo to that plug



I get continuity !! Like I said, all the other speakers work so I am at a dead end at to why the passenger door doesn't have any continuity, and why this plug does... Anyone know what the plug under the dash is for?? BTW, the plug on the left has matching wire colors as well, but no continuity to the speaker wires in the door either. If I have to I can run new wires to the door, but that's a real PITA...any ideas guys? Just want to make sure to PO didn't disconnect stuff and just leave it hanging that is needed...

I know some vehicles of this era had a "Monsoon" delco amp located right about there, which could explain the plugs. Let me see what I can unearth. Did everything work before the radio swap? Or is this what started it?

So I can't say for sure since I have a 1998 manual, and apparently these were ONLY in select 1997 GTPs. This interestingly is where the myth started that the bose amplifier doesn't actually amplify the front speakers. This: http://www.grandprixforums.net/threa...bout-stock-amp little baby amp is what should be there. I've seen a few in the junkyard, but never peaked my curiosity. Apparently, no one has the pinout for these connectors at all! I'm going to try to locate one of these in the junkyard and use a test light to at least find the color configuration for the front door speakers. I'll let you know.

I agree with your conclusion there, and the fact the radio was missing points me towards audio work. It is possible that the rear speakers have been spliced into somewhere are re-wired, causing this. I would see if you can see any "custom" wire work behind the dash. I'd double check your wiring too just in case. Personally I wouldn't mess with it and just run new wires, the stock ones are way too small for my taste anyhow. But I'll see if I can't make my own wiring diagram from junkyard cars tomorrow.

That connector is for the 97/98 only premium sound system amp. If you have 4 speakers in the back window you have that system. Without the amp there the 6x9's in the back will not work but the small ones will. That amp doesn't power the front speakers but is spliced to them.

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There's a diagram of the connector for ya.

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Originally Posted by 1FastGP

There's a diagram of the connector for ya.
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I almost sent the same diagram, however that's the exact one for the bose amp. I'm curious if it is the same or different especially since there's two plugs! I'd double check everything on this chart and be skeptical of everything

I got that diagram off all data so it should be right I used it to reinstall the same amp in my 98 after the p.o. cut the connector and took the amp out. Knowing gm they probably used the same connector just moved it to the trunk for the bose setup in 99

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Originally Posted by 1FastGP

I got that diagram off all data so it should be right I used it to reinstall the same amp in my 98 after the p.o. cut the connector and took the amp out. Knowing gm they probably used the same connector just moved it to the trunk for the bose setup in 99

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Nice! That's good to know. I wonder what the pinout of the second connector is though, and what wires need to be spliced. My experience is mainly with the factory bose amp. I've done way too many stupid upgrades to my car.

Originally Posted by wstefan20

Nice! That's good to know. I wonder what the pinout of the second connector is though, and what wires need to be spliced. My experience is mainly with the factory bose amp. I've done way too many stupid upgrades to my car.

I don't really know on that other connector under there all 3 of my GP's have it and it's never had anything plugged into it in any of them and I don't think it has anything to do with the radio.

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Originally Posted by 1FastGP

I don't really know on that other connector under there all 3 of my GP's have it and it's never had anything plugged into it in any of them and I don't think it has anything to do with the radio.

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well that just gives me an excuse to rip a grand prix to shreads in the junkyard to find out! haha

Confirmed, that's the 97 amp plug. I'm still at a loss what the other plug is for. Traced it back as far as I could. I think it's for some other accessory that another w body car has but not ours since it was unplugged on three 97 gtps in the junkyard. I'm really curious now!