My son's 850 just did the following. When he used the drivers window, the radio began making a squealing sound. Then the headlights would randomly go out and come back on. Sometimes it would be fine for 15 mins, then lights would go out again. He also said the lights would dim or go out when he use the brakess or turn signals, but not always. Anyone have any ideas. Could it be a bad alternator. Not sure if they have a voltage regulator but if so could it be something like that. Any help appreciated.