Hey I just inherited my mom's s80 and there is no sound coming from the speakers. At first the radio wasn't working but changing the fuse worked. I checked the fuse on the amp and it's good. Right now the speakers work when I start the car but after a few minutes of listening to music they cut off. Any ideas on how I can fix this?

 

I'd also like to add that the speakers seem to work fine if I'm parked. they only seem to go off when I'm driving

 

Just a thought.
The radio should turn off when you turn the engine off and then OPEN the door. Maybe the switch on the door is malfunctioning.