The Nissan Path

my problem is that when i switching from low to mid and the 3rd level of climate control fan knob, no air came out, only the highest level working properly, not sure what is going on. AC is working properly, hot air is ok, just fan knob not working unless switch to highest level

Most likely it is your blower resistor. It's a electrical component that controls the voltage to the blower/fan motor. Usually when they go you will only have high speed. Fairly cheap and not hard to do. Good luck.