I've had my 2014 VT for about a week, and just tried to use the nav system yesterday. It functions fine, but does not give verbal instructions, which means I need to keep looking at screen while driving. I've paged through all the menus, and I can't find a volume control of any kind. I've also fiddled with the vol knob, turned the AV off, pushed the map/voice button before, during and after operation, and even pushed and held button. I can't find the key! Any advice? Thanks.