If you have the 811 radio, not sure about the others..there is a small switch located inside the radio itself. It has 4 small wires that plug in with a white plug to a little board that controls the volume. This thing gets real loos. What I did was to actually bend the pins a little to make a tighter fit and have had no problems since. This was after I checked out the wiring to the speaker and it all checked fine. You will have to actually remove the radio and pull the sides off it to do this. May or may not be worth yourt time. Good luck.