- won’t that just turn up the radio volume ?

 

No...depending on what mode you're in the volume will increase in that mode. If you're listening to the radio and push the joystick up the volume will increase on the radio. If you're talking on the phone and push the joystick up the phone volume will increase. Same with the GPS, if you want the volume to increase get her giving you directions and while she's talking push the joystick up and she will get louder.