2003 Bose - Replaced headunit and have "feedback/hissing"

[MichaelG]

2003 Yukon SLT Bose (no rear sub)

So I replaced the factory headunit with a China android operating system headunit which works amazingly well.

I got the Metra Harness adaptor kit and got everything installed and working properly.

The only problem I am having is that well the volume is very loud (on the lowest setting) and there is a little bit of a "feedback/hissing" when there is music playing (does not get louder or quieter based on volume).

My theory is that there is an internal amp in the new headunit and that is feeding the factory Bose amp which is essentially double amping the speakers making them louder on a low volume setting.

I see people talking about an adaptor harness that's around $100 or so but I have not found any links to it or what exactly its used for.

I also bought a factory sub box and would like to add a 8" sub in the back, is there anything special I would need for this?


I have been living with it for a couple months now and I would like to finally get it figured out.

 

[mijohnst]

You have Alternator whine and is probably caused by a faulty ground somewhere in your wiring. I had the same problem in my wife's Yukon when I added a headphone jack into the XM wiring behind the glovebox. I thought I had a good ground but I ended up putting a line filter in and now it's gone. Good luck with finding your issue. I know these things can be frustrating!

 

[drakon543]

it could very well just be a bad hu. you say China android hu did you buy a cheap no name android hu? ive used some pretty cheap hu myself in the past and it didnt work out as well as id hoped. outside of that we can try to run down some other possible issues for you. as mijohnst stated you could have an alternator related issues. alot of times as they stated a bad ground is the typical culprit. next up the metra harness kit you installed you need to make sure the wires are taped up well not just bouncing around. you should also check and make sure the harness kit and factory wires are not laying ontop of any other wires. im not sure how noticeable your feedback is but if its slight it could just be interference from something the wires are laying on. disconnect the ground your using and try a test wire to the main grounding point up by the battery. if that helps the feedback make your own grounding point somewhere else and dont use the factory ground wire. as for the volume issue im not sure some more info on your hu might help me figure that out. im aware alot of better headunits have been using more internal features like crossovers and specifying what's actually hooked up to what channel. something could just be set wrong for your setup by default and needs to be adjusted.