Another GM Wiring Harness Question

Shelbrain
10+ year member

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Which wiring harness do I need for a 2005 Impala w/ Onstar and Premium Sound?

I am getting confused because almost all the harnesses I see are for Bose systems...I don't have the Bose system, but should I still get this wiring harness because I have a factory amp under my rear parcel shelf?

I could care less about retaining OnStar if that matters.

Can someone please link me to the correct wiring harness for this car? Is it this?

http://www.cardomain.com/item/PERGMAH24B

Edit: I will be using an aftermarket Alpine radio and amplifiers if that matters...

 
the T harness works fine, but more work than is really necessary. get a peripheral GMCO. it gives you a retained accessory output from the module, so you don't have to track down an acc wire for the radio. just wire it up like any other harness, and plug it in like any other harness, and tuck the chime module behind the dash. done, no more difficult than installing a radio in any other car. no additional wires to run, it's easy. it does come with RCA ends on the speaker wires of it for bose applications, just cut the plugs off and wire it up like normal speaker wires. the amplifier should be on the bottom side of the back deck. it is standard GM colors going to the speakers, to make it easy you can run your amplifier wires there. the colors are front L = tan (+) and gray (-). front R = light green (+) and dark green (-). rear L = brown (+) and yellow (-), and rear R = dark blue (+) and light blue (-). if you want to run new speaker wires into the doors, it is also very easy, as the door boots are enormous. you could drive a honda civic through those door boots.

 
According to this link, "The GMCO is not compatible with OnStar or Premium Bose systems (these vehicles require the GMAH24 or GMAH24B, available separately), but is compatible with standard (non-Premium) Bose systems."

http://www.cardomain.com/item/PERGMCO

Does this mean I cannot use this harness or does it mean that I just won't be able to use the OnStar?

 
if you want to retain onstar, then you need the gmah24 and the chime for that. if you could care less about onstar, as you said earlier, then the gmco works perfectly fine. and you don't have premium bose either, so that isn't an issue. it is an amplifierd system, but not bose, nor premium bose. the gmco will work fine, losing onstar (not a big loss really...) //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 
sorry this wont help but Impalas with the premium sound are a female dog to do any thing related to audio in it. (My mom has an 04)
there's nothing difficult in any way about an impala. trust me, there are difficult cars out there... the impala just doesn't happen to be one. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif they might look difficult at first, but looks can be deceiving. once you start getting into it, they really aren't bad at all. i'd rather do an impala any day of the week over a bose 300z //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 
if you want to retain onstar, then you need the gmah24 and the chime for that. if you could care less about onstar, as you said earlier, then the gmco works perfectly fine. and you don't have premium bose either, so that isn't an issue. it is an amplifierd system, but not bose, nor premium bose. the gmco will work fine, losing onstar (not a big loss really...) //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
That's exactly the answer I was looking for...thanks! Off to ebay...

Now to my next question...how can I let the factory amp know that I am using an aftermarket amp instead? If I run brand new speaker wire to my new speakers, will there be problems because the factory amp is not being utilized? If I use the GMCO, is there any harm in just removing the factory amp altogether?

 
Isnt Onstar an option that cost money? If so why would you buy it and not want to use it anymore?
Unfortunately, most new GM vehicles come with it standard...they gave me a trial of the service but I never even bothered...

 
That's exactly the answer I was looking for...thanks! Off to ebay...Now to my next question...how can I let the factory amp know that I am using an aftermarket amp instead? If I run brand new speaker wire to my new speakers, will there be problems because the factory amp is not being utilized? If I use the GMCO, is there any harm in just removing the factory amp altogether?

there won't be any problems not using the factory amplifier. you can run new wires altogether, which really ins't hard in that car. or the amp should be on the bottom side of the back deck, between the 6x9's. you can grab the factory wires there if you feel lazy and don't want to run new speaker wires. tan/grey and dark grn/light grn are the front speakers. light colors are positive. brown/yellow, and dark blu/light blu are rear speakers, dark colors are positive in each set.

good luck //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 
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