Why does the sound my Audi A4 Bose Symphony fluctuate loud and soft only when it is hot outside?

if you have the symphony sytem you have to rplace all of the speakers in the car i have the same one. you have to do this becuase each speakers has its own mini amp powering. the only problem i cant fix now is the am/fm is still really fuzzy unlike when i had the symphony installed

Audi Bose Radio Audi Gamma CC Radio Audi Delta CC Radio Audi Concert Radio Audi Symphony Radio which one of the above is your system?

On my '03 A4 it is in the trunk, on the pass. side. You have to remove the trunk floor and carpet on the right side of the trunk and it is bolted to a bracket. I removed the whole bracket. Dealer wanted $800 US. Found one on eBay for $65.

You just go to the link I attached I'm sure you will get the solution of your problem

2004 Audi A4 Workshop Repair Service Manual PDF Download

all that is, is the speapers cant handle the sound

it is in the boot o/s/r below covers

i had same problem with 01 a4 bought from arnold clark .kicked up a fuss and they got it repaired for me, this was nearly 2yrs ago and it's been perfect since so i would say all you need is good audio engineer. by the way audi also told me the radio needed replaced

leave it to a specialest or maindealer

Hopefully you've gotten this answer already, but this might help someone else, too. The amplifier is behind the rear passenger trunk panel. You have to pull out the middle plastic piece that goes over the trunk latch, put the trunk luggage spacer up, and pull the panel out. There is a 12v outlet, domelight wire, and pop fastener, then just pull hard to get the 2 clips. I have a symphony 2 BOSE, and there is no subwoofer, but I think they are in the same place if equipped.

I have the same problem. Did you get anyone to help you? I have the same car. A4 1.8T 2005 with the Symphony factory radio.