Radio/tape Cd Player problems of the 2007 Lincoln Navigator

The contact owns a 2007 Lincoln Navigator. The vehicle has a speed compensation volume control for the radio which would raise or lower the level of sound according to the environment. The contact stated the radio would independently fluctuate from high to low without warrant. The vehicle was taken to an authorized dealer where the radio was replaced. The failure persisted. The contact manually disengaged the speed compensation mode but the failure continued. The radio manufacturer advised replacing the radio a second time. There were no further repairs. The failure mileage was approximately 35,000 and the current mileage was approximately 37,000.