Intermitten Buzzing 05 Envoy SLT with Premium Bose UQA

[Bill05EnvoySLT]

I am open to any suggestions to resolve this.

The most annoying problem i am finding now is the bloody radio! Current config is xm/Onstar/Bose 6 disc indash premium system.
Buzzing coming at any volume when radio is off all is good until the warning buzzer activates (seat belts/Brake/onstar phone ETC)
if i politely SLAM the passenger rear door it seems to go away, i have inspected all wires in the door, pulled rear speaker and checked connections, pulled up the sill plate and checked for pinched wires there, nadda, have looked under the rear seat nothing. when speakers are buzzing seems to be coming from right rear seat speaker. but also seems like right channel drops out completely.
I have read somewhere that the AMP in the 2005/2006 is located on passenger side behind seat in cover under rear glass?? other post say under the center console. anyone confirm its real location. i have also seen some post showing that the factory had bare bleed wires on the harness that may contact another lead? I do have rear audio controls and verified the plug connections and they appear to be fine, i can use headphones in either port and nothing changes. (have digital connections not the manual settings) I thing the amp connections may be the issue but was hoping others have had better success solving this issue. Also when system starts buzzing i get what also appears to be an alternator WHINE. the strange parts is that hitting the brake will cause an auditory pop in it as well. or any momentary electrical surge (turn signal,door lock, power window etc...)
To add to this note. - when you turn off the truck and then restart it appears to go away, sometimes it will return sometimes not. - Also noticed if i have a passenger in the rear seat it happens more frequently (again checked for bad wires nothing-why i think the amp may be there)

Options Sticker image attached!

 

[Mooseman]

By any chance would this buzzing or whine coming from the driver side pillar just behind your head?

 

[DAlastDON]

I have only owned the vehicle since April. I have/had the same/similar gremlin. Buzzing/alternator wine out of the right rear speaker. When the factory bose single disc head unit was in there it happened once in may and about four times in June. It never occurred at a time that was convenient for me to properly trouble shoot it though.

A couple of things have been changed up since the last time since the right rear made the noise in June. First the voice coil seized up due to a apparent moisture problem. Water poured out of the rear of the speaker. Replaced it with another matching bose speaker in July. Second the stock head unit got replaced with an aftermarket head-unit and PAC RP5-GM11 module/harness. Installed in September. The buzz/alternator whine has not occurred since mid June. One of those two things could have been the cause of my problem or the gremlin is hibernating or moved on to other circuits.

 

[Bill05EnvoySLT]

By any chance would this buzzing or whine coming from the driver side pillar just behind your head?

The answer is no . i know about the little fan in the Pillar. this is a loud audible sound coming from the speaker on the right side. when i turn off the rear audio system it quiets momentarily then comes right back. just like changing the channel on the system..
i know politely slamming the door right rear passenger door seems to make the buzzing stop. i think i read the amp may be located on the body panel behind rear seat. i tapped it by hand when it started yesterday and it appears to have stopped since then. only time will tell.

 

[Bill05EnvoySLT]

I have only owned the vehicle since April. I have/had the same/similar gremlin. Buzzing/alternator wine out of the right rear speaker. When the factory bose single disc head unit was in there it happened once in may and about four times in June. It never occurred at a time that was convenient for me to properly trouble shoot it though.

A couple of things have been changed up since the last time since the right rear made the noise in June. First the voice coil seized up due to a apparent moisture problem. Water poured out of the rear of the speaker. Replaced it with another matching bose speaker in July. Second the stock head unit got replaced with an aftermarket head-unit and PAC RP5-GM11 module/harness. Installed in September. The buzz/alternator whine has not occurred since mid June. One of those two things could have been the cause of my problem or the gremlin is hibernating or moved on to other circuits.

I too had an issue with moisture in my rear passenger speaker, replaced it as well. the buzzing sound appears to be coming from the right channel I can hear it from the front and rear speakers. only on the passenger side though..

I need to verify the AMP connections. that is where I think the problem resides.

But hopefully your gremlin is gone for good.
I have heard it could be a bad ground, a bare wire, a bad connection to the RES. could be a pinched wire in the door sill plate, pinced wire under the rear seat.
heard the amp is under center console, heard its behind rear passenger on passenger side under the cover.
at this point who knows? Lol...Ill be checking it all out.

 

[Mooseman]

I read in another thread that it could be a bad speaker. Maybe water got in it and it's grounding out a bit and causing the noise. Could also be the wiring starting to break inside the door jamb inside the protective rubber from flexing, which would jive with the door closing thing.

The amp is inside the rear panel. Can't remember which side but I know that in EXT's it's on one side and shorties it's on the other. Edit: Since the EXT's HVAC is on the passenger side, I will assume that the amp is on the passenger side in shorties.

I'd would investigate around the door first before messing with the amp as closing the door seems to affect it. I know you said you did but maybe the strands inside the wire are breaking.