If i remember correctly there is an inline fuse for that unit (more than likely tucked behind the radio) check that first. if its not there, just trace the wire back (from the changer) to its power source and see if that is getting power, there might be a factory fuse blown... let me know what you find. As for a replacement controller, i would contact Jensen directly, most of the time they can sell you one for a reasonable price. Why makes you suspect the controller, does the unit seem like it is still functional?