Couple of things I will definitely check out! Im at work till midnight right now. It was weird though like the volume had an anchor tied to it. I could turn the knob and it would go up slightly but then turn right back down to no sound at all. The speed of the vehicle had no effect on any of the sound. I messed around with during the 5 minute ride from the store where it begin till I arrived at work. Cut the truck off and let it sit for a minute, started it back up and volume still would not stay turned up. It had been fine all day, I went into the store and when I came out and got back in my truck is when it started.