Picked it up Friday ...42000 km. air doesn't seem to function properly..took it back today and noticed with ac on and vent control set to recirculate,,,seems better, but will fluctuate back and forth to fresh air ..and ac light will cycle on and off s well? Could this have to do with hvac calibration ? (not sure Nissan dealer will know how to fix this problem?) do engine fans always go on (with cool engine) when ac is on? Also read something about battery voltages...runs at 12.6-8 for a while then occasionally high 13-low 14,,, some kind fuel saver mode in the ECM ?