I wondered this after having my LEAF for less than a week. AC and Power Steering typically have pumps—AC has a compressor, and power brakes have a pump. When I turn the car on, I hear a motor so I assumed it was the drive motor at some slow idling speed to run the two pumps OR each had it own electric motor. So I asked Nissan and the answer I received was that each has its own motor but still uses the Li-Ion to run them. Just FYI