Hot air through vents with fan off

[CountryBoy704]

If I have the AC off and the vent selector to anything BUT off, I'll get a good bit of hot air coming through the vents which seems to stop when the truck stops. So I think I'm pushing engine bay air into my vents somehow? AC is definitely one of my weak points, anyone know where to start looking?

 

[Mazda]

If you have the cold ----------hot temp slider to anything past halfway on the HOT side your will get HOT air. The heater will be "ON" no matter if the fan switch is on or you have selected anything on the vent selectors.

 

[Mickey Bitsko]

If its hot during the day you will have hot air come in through the exterior vent, in the winter when its cold out the exterior vent will draw in cold air anytime the truck is moving
If you don't want any air anytime put the vent/ac/defrost/floor mix selector to the OFF position.

 

[CountryBoy704]

Interesting I guess it's functioning fine then? Didn't expect to have to run it to 'off' in order to shut off airflow