Actually, it has nothing to do with the occupancy. It is one of the "Convenience Features" settings. Go to "Setup" - "Vehicle Settings" - "Seat" - "Heated/Ventilated Features" - "Auto. Controls that use climate control settings". This is based on whatever temperature you set in car climate control settings and it will keep the temperature of the driver's seat warmer, air ventilated seat and heated steering wheel to be controlled automatically, based on the inside and outside temperature of the vehicle ( when the engine is running).