Audio Systems: 05 Tahoe Stereo Problem, premium sound system, technical competency

Question
Tahoe is equipped with a "premium sound system" - Stereo/CD Player appears to be a standard GM but speakers in door are Bose. When I turn on the ignition an electronic "powering down" sound is heard coming from the drivers side door Bose Speaker. Lasts about 10 seconds. Happens if stereo is on or off.  Then intermitently strange electronic feed back will come from that same speaker - high pitch whining sound that will increase and decrease with acceleration.  Took the vehicle to the dealer for a warranty repair and they replaced the wiring harness from the amplifier to the radio. The problem went away for about a week.  Then the stereo started to briefly cut out from time to time. Next the above described problem has started all over again.  When I take it back should I ask for them to replace all the components? Stereo, Amp & Speakers?  Any idea what the problem really is?

Answer
I think this problem is in the interface with the data system of the car.  The wires to the speakers are, in the newer cars, used for other than just feeding the speakers.  And, sometimes data pulses get into the power lines that feed power to the head unit.

My recommendation is to have your dealer contact with the region or area people on this one as it is beyong the technical competency of a local shop.

It may be a simple filter in the power system of the car, but I don't think so.  And, replacing the entire system will be a waste of time if the problem is related to the cars electrical system and not the entertainment units.

So, tell the dealer that you talked to an "expert" from allexpert.com and recommended getting advice from the region office or factory experts on this one.  It is not going to be an easy one, in my opinion.

Hope this gets you going the right direction.

Cleggsan