Noticed last ride that when the bike was off but radio on the volume went up on its own. Especially when I tried go turn it down with my hand controls. Today on my ride down to the beach it would go all the way up when I slowed down only. Had to shut it off because it was full max no adjusting it lower. On the way home everything was fine. Any suggestions. I have a pioneer head unit with PAC hand controls and 2 amps.