The heater and thus defroster no longer work, only cold air comes out. A Nissan service center diagnosed the issue as a stripped out part of the blend door actuator. The whole heater box would need to be replaced to resolve the issue. In winter driving, the lack of defroster impairs visibility and turns off the automatic forward braking system. The fault light for the forward braking system comes on when there is windshield frost/fog. The first signs of this issue appeared as intermittent failures of the heater failing to turn on, but resolved on the next drive. Eventually, the heater/defroster permanently failed. From searching the internet, this blend door actuator issue appears to be prevalent among other Rogues.