Replacing aftermarket radio with OEM radio(2008 Grand Prix) (Page 1/1)
starlightcoupe OCT 28, 12:13 PM
I bought a 2008 very low mileage Grand Prix (38K miles) that has an aftermarket stereo system with a boombox bass speaker in the trunk. I like the OEM CD/radio combo so much more than the $99.95 Alpine the PO installed.

Looking on the internet, I saw that I have a few options if I buy an OEM radio and install it. I can buy it and have the dealer "reprogram" it so I can use it. In reality all they do is over ride the existing VIN# in the radio's EEPROM.

My second option is to remove or unsolder the Vcc (12V) pin on the EEPROM but some odd things happen if I do that such as losing presets.

Third option is to remove EEPROM, use a PICkit, read the EEPROM, determine what the lockout code is and change it with Pickit and reinstall the EEPROM.

Am I making this harder than it is? Are there other options for unlocking these radios?

I htink the original installation was a slash job because a lot of things associated with the radio such as the ding dong dingy ringy thingy doesn't warn me about anything. Also, the existing radio's presets are gone when you turn it on. The radio reception is not good--in short, I'd be better off with a 1975 Chevy truck radio than the Alpine.

Oh, forgot--How are these boom-box-in-the-trunk powered and signals usually fed to them? With a wire or wires under the carpeting?

Has anyone any suggestions and/or experience with these OEM radios?

Edit: I can't find anything other than a color code chart online for the 2008 Grand Prix radio. I work much better with schematics--anyone know where I can find one?

TIA

[This message has been edited by starlightcoupe (edited 10-28-2013).]

Khw OCT 29, 08:41 AM
As to the stereo, that sounds about right for options.

The no ding a lingy thingy is because they apparantly didn't use a PAC adapter when they installed it. The car uses the stereos speakers for warning chimes and such so without the adapter to integrate the stereo with the computer, you loose those.

As to the boombox. On the back of the Alpine you should find some RCA cables plugged into it. Those "should" be ran under the carpet somewhere. Follow them back and it will go to where the amplifier is/was. Then you should be able to follow the speaker wires to the boombox and the power/ground wires back to their source and remove them, if that's your intent. If your intent is to use them with the stock headunit, your going to need a high level to low level convertor if the amplifier doesn't have high level inouts or your missing the plug in for the hihg level inputs if the amp has them. I've never seen a stock headunit with low level RCA outputs that can go to aftermarket amps.

[This message has been edited by Khw (edited 10-29-2013).]

starlightcoupe OCT 29, 02:09 PM
Thanks for your reply. I totally forgot about RCA outputs on the Alpine. I want to take out the boom box so I will probably just disconnect everything behind the Alpine and leave it without power or signal. On the other hand, I really like listening to Zeppelin with that boomer--man, that thing makes John Paul Jone's bass sound like it coming from the back seat!

After I posted the original question, I found some kind of adapter and maybe it is the one you recommended and I will buy one of them. I will probably go with the one you recommended because my install days are long past me. Thanks again.

Richard

[This message has been edited by starlightcoupe (edited 10-29-2013).]

starlightcoupe NOV 05, 06:19 PM
I decided to take an alternate route and put an earlier model GM radio in the Grand Prix but the GP has a shark fin antenna. I am pretty sure these are powered antennas and if so, what voltage goes to it from the radio? GM wouldn't want to reinvent the wheel so I'd assume that they use the 12V battery voltage since it is everywhere in these cars.I have a pretty good schematic for the radio harness and wiring and it only shows a wire going to the antenna but no voltages.

The late model factory radios are a PITA because the BCM appears to turn on the radio with a signal from the radio itself and it keeps presets such as clock, radio station presents, through a data link. My new radio is from a 2004 TrailBlazer and the wiring is definitely not the same but I have figured it out except for the antenna.

Any clues???

Richard

[This message has been edited by starlightcoupe (edited 11-05-2013).]

Khw NOV 05, 11:22 PM
I don't know but like you I would suspect that it's 12 volts. I'll see what I can dig up and see if I can find a definate answer if someone else doesn't chime in before I find one.
starlightcoupe NOV 07, 12:19 PM
I should get the replacement radio by Friday and I will assume that the antenna works on 12V until one of us hears otherwise. Thanks for your help. I can always put a milliammeter with a 1K resistor in series with the antenna lead and see if it draws excessive current. I think the only voltages in the radio that are not 12V might be the 5V data link.

I tried calling an installer and they didn't know the antenna voltage either. They knew which wire to hook up and its color, though!

Thanks again!

Richard