Static / Hissing through speakers
Hello everyone, I have an issue that I'd like to get some feedback on if possible. My car has a hissing/static noise coming through the speakers. It is not ridiculously loud but it is noticeable.
1. Static only occurs with the engine on. It does not matter if the radio is on or off. Engine off, no static. Because it doesn't matter if the radio is on or off, the volume knob makes no change in the static/hissing volume.
2. Sound comes from all speakers, it is not confined to only one. Front and back.
3. Subjectively, it appears to be louder on cold mornings than or warmer days. But that could be all coincidence or in my head.
4. The car has no nav, just AM/FM with CD player. It came from the factory with the Aux and USB inputs. It's a late 2008 production. It has no aftermarked anything.
3. The actual sound qualify from the system is perfect. Cranking up the music sounds just fine, no problems at all. Turn the music really low and you'll notice the static/hissing present.
I'm taking the car in to the dealer this saturday. I'll have them look at it but I'm weary of them trying to pull one on me and tell me that I need new everything costing me thousands.