More questions ! give me a break i'm still a F@%$@*# New Guy .i replaced the factory setup with a new new clarion double din tv/dvd setup in front and added 2-7" headrest monitors in the rear i used the correct gmos-01 onstar module to retain the use of all factory components but now i have a hissing sound out of the speakers along with engine noise that changes with rpm. I have all my grounds (radio and both monitors) going to the main radio harness should i seperate the grounds and attach then directly to the trucks frame or you think thats fine? anybody have issues with onstar interface modules as far as noise or strange sound are concerned?

 

Well, unfortunetly I have even read from a hummer engineer that he did the same swap and had a bad hiss noise when using onstar. You can try to isolate grounds to different anchor points, try a ground loop isolator to see if that takes any of it away. Unfortunetly this isn't the type of thing that I or anyone else for that matter can diagnose over the internet. I have seen cases like this when I was an installer at a shop and some of them took HOURS to diagnose. Ground loop noise is a complete bitch to get rid of. If I were you I would wire temporary ground to different locations and see if it gets better. After that if no change move on to speaker wires...make sure they are shielded from ALL power wires. Somewhere you are getting voltage into your speaker wire, just keep going one wire at a time till you see or hear an improvement

 

Yea I also have an aftermarket radio setup and also get bad engine noise. The one thing I
hate besides the noise is the fact that there is no way to adjust the volume easily for the Onstar.
I have been thinking about trying to put in an external variable resistor to adjust the volume level,
any other ideas would be appreciated.


Jim

 

this is supposed to allow you to adjust onstar volume and mute it through a new radio, are you using this?

http://www.logjamelectronics.com/soundigistarb.html

 

Is the gmos-01 onstar interface going to give the dealer trouble reading the bcm or any other computer issues? I heard the pie module requires you to remove the factory fuse for the radio before hooking up to the dealer computer.. is this true for most interfaces ?

 

I know a few require removing the fuse, best bet would be to call pac. audio...they are the experts and will help you through it.

 

Has anybody done a new radio install (something other than a factory replacement) that has not had any hiss/engine noise/whine if so what module/interface did you use ? I used a metra kit and it kinda seems @%#&$^# so far

 

I had a BAD engine noise when I had my local shop install me Eclipse. I used all PAC interfaces. The tech at the shop spent HOURS, but finally got the noise down to a bare minimum. I honestly don't hear it unless I REALLY try. And no-one who is in my rig has EVER heard it. I ASK!!!

 

On the power lead that powers up the unit (amp or head)..Put a .05 Mfd capacitor NON electrolytic(get it at Radio Shack) on the +line to a ground pointsomewhere...The noise is alternating current signalsfrom the altenator..it rides on the DC level like radio waves do in amplitude modulation..The cap acts as a band pass filter and traps the AC noise to ground.