the car i have is an 09 sstc with onstar. now i have a pioneer avhp-6000 double din touch screen 6 disc dvd player i just recently got this headunit installed into my car and the gmac harness was used for the install everything was all good for the first 3 or so days and then and still to this day i get a random sound coming from my passenger side tweeter even when the volume is turned down the sound is still there and if i turn the headunit off theres a loud poping sound and then the stereo shuts off and the sound stays everything else in the car is stock using the stock amp and stock speakers i do have an aftermarket amp but thats for my subs. also as i drive around the sound coming from my tweeter will shift from passenger side to drivers side and sometimes theres no sound at all its been in the shop 3 times now and everytime it comes back with the same problem and they cant figure it out ive had the pac module replaced and that hasnt got rid of the sound also i can hear the sound of my windows rolling up and down though the tweeter also when i give the car more gas the sound gets louder and quiter as i left off the throttle

all my equipment came out of my other car which was an 07 ssna without onstar and on that car i had a different harness and i never had this problem

im at a loss as to what to do with it now since this new install in my new car has costed me almost 700 bucks just to put my equipment into my car again and in the new car its just not working right does anyone have any ideas on what would cause this sound to be in my tweeter

 

Sounds like engine noise..does it get louder as you rev your engine?? Describe the noise is it a high pitched squeal?

Damn my bad I didn't read all your post..but yes that's engine noise coming from your speaker amp...you need higher quality RCA cables or a ground loop isolator

 

try putting a piece of wire from the rca to the chassis on the pioneer.... grounding the rca shield