Cowl ventilator control knob vs heater blower switch (1 Viewer)

[Brasi]

I recently wanted to see if my heater was functional in my 72 FJ 40. In CA there is not much use for the heater but I wanted to see if it worked anyway. I pulled the rear and front heater blower switches individually and saw that there was heated air flowing. I did not know the function of the cowl ventilator control know. What is the function and do I need to do anything with it while utilizing the heater?

Thanks

 

[DSRTRDR]

no, the airflow pull knob has nothing to do with the heater - it simply opens the hood vent by the windshield to let fresh air into the cab

 

[Brasi]

Got it thanks!