I tried everything and I still can't get this fixed!!
My Bose system has no base, its flat.. If its cool ouotside it works fine, as soon as you let the car sit in the sun and get the inside hot it dies. What it sounds like is someone turned you base control all the way down. Now, if I let the car sit there for a day in the garage it pops back till the next time it get hot in there again.
I have tried replacing the signal processor (amp as GM calls it in some places in the repair manual) and that did not make any change. It seems to be getting worst.
I'm at a loss now, don't know if I should try replacing the head unit or not.
I don't think there is anything else it could be? I would think if it was a speaker amp, only one speak would be effected..