Sometimes during winter my cruise control also stopped working. I'm not sure why, but I think it might have been because the windscreen was cold and had some condensation in front of the camera, so the camera couldn't see well enough. I believe the camera needs to see the car in front of you well enough, so that the adaptive cruise control can slow down the speed when you get too close to the car in front. A traditional (non-adaptive) cruise control wouldn't have this problem. My solution was to use the speed limiter instead of the cruise control, until the cruise control started working again. Maybe it took some time to warm up the windscreen, to clear up some condensation, but that's just my guess.
