Hi Guys.

My Mazda 3 2006 2.0L has interesting symptoms. I'm not sure that's normal.
So, if my fan switch is turned off everything looks good but in hot engine cooling fan doesn't turned ON, but when I set fan switch to 1 or 2,3,4 I can hear relay change position and my cooling fan turns ON and then same time also A/C compressor is turns ON for maybe 20sec. then OFF for 20sec. and over and over again but A/C button inside is OFF and it's not blows cold air only then I push the A/C button the air is cold.

Is it normal?

 

Yes. The engine cooling fan only runs for 2 reasons, and this is on any car. The obvious one is the engine is hot and needs to cool down. The other is the A/C. Part of your A/C system, the Condenser, sits it front of the radiator. The condenser removes heat from the A/C refrigerant. A pressure sensor in the A/C system controls the engine cooling fan and turns it on and off as needed to cool the condenser. That said, when you turn on your defroster, the A/C kicks on to help dehumidify the air and aid in clearing your windshield quickly. All makes of vehicles are set up this way, you just happened to notice it now but it is normal operation