I recently had an aftermarket stereo installed. I retained my steering wheel and OnStar capabilities through the adapter kits. There is now a high pitch whining sound that comes through the speakers that gets louder with acceleration. It sounds like an alternator issue or bad ground. It is not present when I am using OnStar. The installer troubleshot the vehicle for 1 week and the whine is still there, the best they could do was install a loop noise filter to reduce the whine. I believe that the OEM BOSE amplifier is still being used to power the OnStar. Questions:

1 - Does anyone have any suggestions how I can fix this?

2 - Can I simply run OnStar through my aftermarket system and bypass the BOSE amplifier altogether?

Aloha

 

I just got done with a major upgrade project in my H2 which included a major A/V refit. If you want to keep Onstar you must use the factory amp and at least one of the bose speakers. This will also retain the bells and warnings from the vehicle, like keys in the ignition, door open, warnings buzzer, etc...

The noise is coming from the fact the inputs to the Bose amp are not being used so the amp is floating right now, allowing noise to get in it. When I did mine, I tried to make some terminators to fake out the input but I could not get the right impedence so it did not work. But this is where the problem is.

To reduce the noise, I disconnected all the factory tweets at the tweets. Then I took the input cables out of the adapter to the factory amp, these would be the 1 foot RCA jumpers from the adapter box. I used a de-pin tool and removed them so I could add them back later if needed. Then I adjust the output for the warnings, and the amp to reduce the noise to the lowest point but so I could hear the warnings.

The noise is way down now. It is there but you have to listen for it. I plan to do some more with the terminations to make it better but it is livable now.

 

Thanks Quijy. So it sounds like the only way to completely eliminate the noise is to remove the OnStar system completely.

 

i just lowered the input levels on the on-star interface. i have 2 ***** on mine for adjusting and i just lowered them a smidgen and i was fine, i put in a avic-f700bt and replaced the factory speakers with 4 infinity reference speakers and 2 infinity tweeters and the system runs great and sounds a hell of a lot better and have no squeaking or whining sounds

 

You dont have to get rid of your onstar. This is a very common problem that we call alternator whine or a ground loop in the car audio field. it typically comes from a badly ground grounded piece of equipment.You can try to move your grounds on the radio/onstar wiring harness (black wires),or you can buy a noise filter from just about anywhere that carries car audio equipment.I've been installing for about 10 years so if you have any questions just shoot me a line.

 

Maybe I can partake of your expertise. My wifes H3 Alpha came with the stock cheapie radio and I am gonna put in an all in one GPS, radio, B/U camera, etc, since she says she is gonna keep this car "forever". Where do I find a wiring schematic for the 2008 H3 Alpha? I am a retired electronics engineering tech, so I'm not really afraid of the install job, but my wife still works and needs her car, so install time needs to be as short as possible. (my car is a stick Challenger, and she can't/won't drive it!)Thanks for any help.

 

as far as the noise you are getting there is a fix buletin issued by pac (one of the interface companies) you can go to there website www.pac-audio.com the motor whine can be eliminated by adding 1k ohm resisters in line of negative speaker leads. good luck was a life saver

 

I just had some speakers and amp hooked up in my truck. Everything was working fine except i noticed that the back up camera wasn't working anymore when I put it in reverse. So i got my bf, which is a mechanic to fix it. He also had to replace the ground battery terminal and after he did that my onstar/phone/seatbelt light wasnt working. Also my stereo now wasn't turning on when I started my truck like it always did, I have to manually turn it on and off now. Any suggestions on what could be the problem? Hopefully I explained it well enough