ok, what i was trying to do is pool on a nationwide resource of installers and techs who have delt witht his car and this module KT is the only one who seems to think that my time helping is worth anything, with this being said, i understand and respect D'* input an experiance, but i too am coming from experiance when i see these modules are crap, i work for a company which is partnered EXCLUSIVELY with metra, and ia m saying in EVERY sense of the word, the OS modules are junk, if you would like a more complete list of junk metra products feel free to PM me and i will be glad to provide it. i only offer this last point, before you point the blame to the car, look at the part. however since im just another "cook", i am removing my input KT, i wish you the best of luck solving your problem

This really sucks that it is that complicated. I hope someone can help figure this out, not just for me, but for others out there that want to get a cd player in without having to rewire EVERYTHING. Thanks for all the help from everyone so far

First, I don't want anyone to feel offended or get upset

I'm trying to work on a solution, but hopefully from this post everyone will be able to understand why this is a lot more complicated than just a wiring change.

So that everyone understands what we're looking at, here is (in basic terms) how the systems works.

The radio, CD changer and OnStar module (amongst several others in the car) all communicate on the Class 2 data network. This system allows several different devices to "speak" with each other, even though they perform different functions.

The amp in OUR vehicles is NOT a class 2 amp. It is controlled directly and soley by the HU. Whether the amp is biased on or off depends on the status of the 14V reference line.

The OnStar buttons are connected to the VCIM (a single module in the 2003+ MY), or one of two seperate modules in the 2000-2002 MY. These modules, whichever the case is, communicate with the radio over the data bus. When the radio receives a message from the OnStar module, it will change the audio input from whatever is playing (radio, CD, CDX, XM) and use the input from the OnStar mic. At the same time, if the input was originally from the CD or CDX, it will pause the current track. If the radio was off, or otherwise in a state where the amplifier was not turned on, the HU will also turn on the amp via the 14V ref line.

Likewise (for example), if you are listening to XM and change to the CDX, the HU will send a message on the class 2 data bus to the XM receiver (DRR) telling it to turn off the audio output. Next, a message is sent to the CDX instructing it to turn on the audio and begin playing. This is necessary because these two devices share the same audio input on the HU. OnStar has its own input.

The entire function of the GMOS-09 module, is to "extract" (if you will) the class 2 data functions from the OEM HU and perform these "data management and control functions" as a seperate external controller. This is because aftermarket HU'* don't support class 2 data protocols. Without engineering another device to intercept and process these data signals, there is no way to "integrate" the OnStar module(*) to control the amp.

What needs to happen, is to find a fix for the GMOS-09 module. GXP Vince, I may take you up on your offer to help solve this problem. This will ultimately become a collaborative effort with the manufacturer (but not at the help desk level). The reason this is so complex (simply put) is because we're messing around with the computer control of all these devices.

I'm willing to carry on working towards a solution, but this WILL take some time.

The next step for you KTBoom2006, is to try and obtain a replacement module. Hopefully, yours may have been only one in a bad batch.

Edit(*): Minor descriptive and grammatical changes.

It is sometimes difficult with the written word to effectively communicate. There is a lot missing, tone of voice, eye contact, etc.

I see that I have likely pissed people off. If so, I apologize. I could see a lot of distracting input and I attempted to point that out.

FYI, I have PMed FiReDeViL with a personal apology. I hope he can still contribute to the solution.

I am really glad that everyone is working together.

For me, I will be trying to contact the store that we bought to see if they will exchange and if that have one in stock. They are 2 hours from us, so I want to make sure of all of this before I get there. I hope to do this this weekend and I will update from there.

Again, thank you... all of you

we got this, we can definatly get this taken care of for ya apology accepted btw, i cant leave a club member hanging....

GXP_Vince has kindly offered to send me his module. I'll be putting a dedicated effort into a solution once I can haved a closer look. Obviously there are no guarantees, but I'll try and exhaust all possibilites. Updates to follow accordingly.

Does anyone else have an extra GMOS-09 they would be willing to give out if I pay shipping? We took ours back and the store owner said it was customer error is why it didn't work. Even after saying we used a volt meter to test it, he still blamed our installation. Well we have been installing stereo'* for many years..... Anyways, I don't want to start on that. Just wondering if anyone had one just lying around we could use?

This is very disappointing. It sounds to me like the shop just wanted an easy out and not have to deal with the warranty issue. Having read your posts, I certainly had the impression that you weren't new to this type of work, only that you perhaps hadn't worked with these specific cars/modules before. This sort of attitude is quite frustrating.

This is true. I have had 6 cars that have all had different wiring harness and worked sucessfully. The Bonneville is the only car we have ever had problems with. I even went to Best Buy today to ask about installing a Remote Starter and DANG IT, this car is so much trouble. LOL, I have to get a spare key so that we can have another MODULE to get around the security. Everything I want in this car is a pain. But, I am not giving up.

Anyways, I just wanted to say Thank you DDalder for believing that I have some knowledge of car stereos.