I seem to have lost all control of bass (none). Have the factory JBL in dash w/cassette, 6 cd changer in console, and the rear JBL powered sub. The bass control on the radio is just a turning ****. Turning the **** does not cause any increase of bass to any of the door speakers and there is nothing from the rear sub. I checked fuse box near drivers door and under hood. All fuses relating to radio system are good. All of the other radio functions/controls work. Is there another fuse I need to check? Or any Ideas on this problem? Thanks, in advance!!