[Damned04]

I bought my 04 aero about 2 months ago and I noticed when I turn on the windshield defroster my speakers start to cut out (Lose all the treble notes!) after the windshield heats up. Is there a simple fix for this or do I need to bring it in?

 

[ctrlz]

probably not.

Does it have the stock stereo? Which configuration if so?
Which speakers seem to be affected? All of them?

This sounds like the added load of the defroster may be robbing current from the audio. I would check the grounding points in the trunk for starters, because the defroster is probably grounded back there.

If aftermarket speaker wire was run parallel to the defroster wire it might pick up some interference. Kinda doubt 12V DC would be a problem, but they may PWM the defroster grid. Parts of the defroster grid also act as the radio antenna. But those AC currents would be low.

The antenna signals get amplified by a module on the right C-pillar. If you are hearing noise listening to the radio while the defroster is on, that is another likely source. I never listen to the radio, which is why I didn't mention this first!

 

[Damned04]

I'm running all stock speakers and the top mount dash speakers seem to be cutting out.