my alternator died in my volvo recently. once it just didn't start up, and we thought that we just left a light on and the battery died cause it happened over night, and once we got it up and running it was fine but a few months later i had the same issue only once we finally got my car started up every so often when i would slow down or accelerate the lights would dim, radio would dim and lower volume. the car actually straight up died on the onram to a major highway which was pretty goofy. but it was the alternator..